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Prognostic stratification of pulmonary carcinoids into "typical" and "atypical" categories requires examination of large tissue volume. However, there is a need for tools that provide similar prognostic information on small biopsy samples. Ki-67 and OTP immunohistochemistry have shown promising prognostic value in studies of resected pulmonary carcinoids, but prognostic value when using biopsy/cytology specimens is unclear. Ki-67 immunohistochemistry was performed on small biopsy/cytology specimens from pulmonary carcinoid tumors (n=139), and labeling index was scored via automated image analysis of at least 500 cells. OTP immunohistochemistry was performed on 70 cases with sufficient tissue and scored as positive or negative (<20% tumor nuclei staining). Higher Ki-67 index was associated with worse disease-specific progression-free survival (ds-PFS), with 3% and 4% thresholds having similarly strong associations with ds-PFS ( P <0.001, hazard ratio ≥11). Three-year ds-PFS was 98% for patients with Ki-67 <3% and 89% for patients with Ki-67≥3% ( P =0.0006). The optimal Ki-67 threshold for prediction of typical versus atypical carcinoid histology on subsequent resection was 3.21 (AUC 0.68). Negative OTP staining approached significance with atypical carcinoid histology ( P =0.06) but not with ds-PFS ( P =0.24, hazard ratio=3.45), although sample size was limited. We propose that Ki-67 immunohistochemistry may contribute to risk stratification for carcinoid tumor patients based on small biopsy samples. Identification of a 3% hot-spot Ki-67 threshold as optimal for prediction of ds-PFS is notable as a 3% Ki-67 threshold is currently used for gastrointestinal neuroendocrine tumor stratification, allowing consideration of a unified classification system across organ systems., Competing Interests: Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Pulmonary carcinoid tumors are relatively uncommon and have an indolent clinical course. The role of histologic grading and cell proliferation as measured by a Ki-67 index in predicting long-term recurrence in carcinoid tumors of the lung is not defined. We report the largest single-institution study of carcinoid tumors and correlate histologic grade and Ki-67 index with clinical outcome. We reviewed all surgical lung resection cases from 1995 to 2016 with a diagnosis of primary carcinoid tumor. We collected clinicopathologic parameters, including tumor size, nodal status, histologic pattern, presence of lymphovascular invasion, mitotic count, %Ki-67 positive cells (Ki-67 index) using a digital algorithm, time to tumor recurrence, and staged these tumors based on the 8th edition of TNM Staging. The final cohort consists of 176 carcinoid tumor cases with complete data: 165 (94%) were typical carcinoids and 11 (6%) were atypical carcinoids. The Ki-67 index is significantly increased in atypical versus typical carcinoids and in higher stage disease. Only the Ki-67 index and not the histologic patterns or lymphovascular invasion status was a significant predictor of tumor recurrence on multivariate analysis among all pulmonary carcinoid tumors and within typical carcinoid tumors alone. A Ki-67 index cutoff of 5% offered the optimal combination of sensitivity and specificity in predicting long-term recurrence based on the receiver operating characteristic curve. In addition, stratifying pulmonary carcinoid tumors based on a 3-tier histologic grading system (grade 1: typical carcinoids with Ki-67 index ≤5%, grade 2: typical carcinoids with Ki-67 index >5%, and grade 3: atypical carcinoids regardless of Ki-67 index) significantly correlated with likelihood of tumor recurrence. Finally, we propose an integrated staging system unique to pulmonary carcinoid tumors by keeping the original TNM stage for grade 1 tumors, but upstaging grade 2 tumors to stage II, and grade 3 tumors to stage III.

Pulmonary carcinoid tumors are an uncommon tumor in the lung, representing <1% to 2% of all primary lung cancers, and have a relatively indolent clinical course. Because of their low incidence, these tumors do not have a specific staging system. However, since the 7th edition, the TNM Classification for Lung Cancer has been used in these tumors, though the ability of this staging classification to predict prognosis in carcinoid tumors is not well-studied. We report the largest single institution study of typical and atypical carcinoid tumors with recurrence as a measure of outcome and compared the ability of the 7th and 8th TNM Classification of Lung Cancer to predict recurrence in typical and atypical carcinoid tumors of the lung. All surgical lung resection cases from 1995 to 2016 with a diagnosis of primary lung carcinoid tumor were reviewed and clinicopathologic parameters, including tumor size, nodal status, histology (mitotic counts), and recurrence were recorded. The final cohort consists of 205 carcinoid tumors: 188 (92%) typical carcinoids and 17 (8%) atypical carcinoids. Pulmonary carcinoid tumors have an excellent prognosis with a low recurrence rate of 8%. Atypical carcinoids were significantly more likely to recur (median time to recurrence: 3 y) compared with typical carcinoids. By placing more emphasis on tumor size and nodal status in the staging classification, the TNM 8th edition was superior in predicting outcome compared with the TNM 7th edition.

Goblet cell carcinoid tumors are amphicrine tumors whose biological behavior ranges from indolent to highly aggressive, depending on tumor grade. Current grading systems for these tumors are based on identifying an adenocarcinoma arising in the setting of a goblet cell carcinoid tumor, which distinguishes this tumor from other gastrointestinal tract adenocarcinomas. Because goblet cell tumors are predominantly tumors of mucin secreting cells, we propose that they be classified as goblet cell adenocarcinomas, and graded using a methodology that has parallels in colorectal adenocarcinoma grading. We graded a large series of goblet cell adenocarcinomas by assessing the proportion of the tumor that demonstrates tubular or clustered growth. Histologic grade correlated with overall survival independent of stage, with median overall survival of 204, 86, and 29 months for low-grade, intermediate-grade, and high-grade goblet cell adenocarcinomas, respectively. Tumor stage also correlated with overall survival. We also graded the tumors according to previously proposed grading systems, and found that these systems are valid, in that they segregate patients according to prognosis.

The diagnostic criteria of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) are not well defined, and DIPNECH can be mistaken for carcinoids associated with neuroendocrine cell hyperplasia (NECH). In this study, we compared clinical, radiologic, histologic, immunohistochemical, and molecular features of DIPNECH and isolated carcinoids with/without NECH. The study population included 151 cases (77 female patients and 74 male patients), 19 with DIPNECH and 132 with carcinoids with/without NECH. None of the cases displayed molecular alterations or anaplastic lymphoma kinase expression. Compared with individuals with carcinoids with/without NECH, patients with DIPNECH were more likely to be female individuals (P<0.0001), nonsmokers (P=0.021), and symptomatic, and to have an obstructive/mixed respiratory defect, peripheral location of the lesions, and air trapping (P<0.0001) on chest computed tomography, and constrictive bronchiolitis on histology (P<0.0001). Among immunohistochemical markers, DIPNECH was associated with higher expression of thyroid transcription factor-1, CD10, and gastrin-releasing peptide/bombesin-like peptide (P<0.0001). Yet, when a purely histopathologic definition of DIPNECH was applied, 40% of isolated carcinoids also met the diagnostic criteria for DIPNECH, even in the absence of symptoms and/or radiologic abnormalities. Therefore, as DIPNECH represents a distinct clinical syndrome, we suggest the term DIPNECH be limited to cases presenting with respiratory symptoms, functional and/or radiologic abnormalities, and constrictive bronchiolitis on histology.

Twelve lung neuroendocrine tumors with morphologic features of carcinoid tumors but with mitotic count >10/2 mm are reported. There were 7 males and 5 females, with age ranging from 56 to 78 years. Four cases were from never-smokers. All tumors showed architectural and cytomorphologic features of carcinoid tumor, including organoid nesting, insular, trabecular, or acinar growth, and tumor cells with low nucleocytoplasmic ratio, abundant cytoplasm, ovoid to round nuclei, and salt and pepper chromatin. Angulated or confluent nesting, insular or lobular growth pattern was also seen. Nuclear irregularities and anisonucleosis were focally present. Mitotic count ranged from 11 to 61/2 mm. Punctate-type necrosis was present in 8 tumors. Anaplastic cytology, large infarct-type necrosis, desmoplasia, or marked inflammatory infiltrate was not found in any of the tumors. One tumor occurred in the background of diffuse idiopathic pulmonary neuroendocrine hyperplasia. All tumors were treated by resection, and all but 1 patient subsequently developed metastasis, and 7 died of the tumor. For metastatic tumors, 4 patients were treated by platinum-based chemotherapy with no apparent response, whereas 3 other patients were treated by combined capecitabine and temozolomide-novel chemotherapy for well-differentiated neuroendocrine tumor/carcinoid tumor-2 of them responded. This subset of tumor would be classified as large cell neuroendocrine carcinoma according to the current WHO classification scheme, but their clinical and pathologic features appear to have more in common with the carcinoid tumor group than large cell neuroendocrine carcinoma, therefore, identification of this subset may be relevant for further therapeutic management.

Goals: We sought to compare the efficacy and safety of endoscopic ultrasound-guided endoscopic resection (ER) and endoscopic band ligation (EBL) for autoamputation of small duodenal carcinoids., Background: The ideal management of small duodenal carcinoid tumors remains unclear., Study: A retrospective review of duodenal carcinoids over a 10-year period (2002 to 2012) was performed at our tertiary-care teaching hospital. All patients with duodenal carcinoids ≤10 mm in size treated with either ER or EBL were included. The main outcome measurements were the efficacy and safety of endotherapy., Results: A total of 37 patients with 39 subcentimeter duodenal carcinoids were identified. In the EBL group, the mean (SD) tumor size was 6.7±2.1 mm compared with 6.7±1.7 mm in the ER group (P=0.943). The mean Ki-67 index was ≤2% in specimens available for histologic analysis in both groups (16/23 EBL and 15/16 ER). The positive deep margin rate in the ER group was 68.8%. Residual carcinoid tumor cells were detected on follow-up biopsies in 1 patient after EBL, and 2 patients after ER. All underwent subsequent successful endotherapy. No adverse events occurred in the EBL group compared with an 18.8% adverse event rate in the ER group (P=0.066)., Conclusions: Endoscopic ultrasound-guided EBL is a safe, effective method for removal of small superficial duodenal carcinoids and seems to be a lower risk alternative to conventional ER with cautery.

Pulmonary carcinoids are neuroendocrine tumors histopathologically subclassified into typical (TC; no necrosis, <2 mitoses per 2 mm) and atypical (AC; necrosis or 2 to 10 mitoses per 2 mm). The reproducibility of lung carcinoid classification, however, has not been extensively studied and may be hampered by the presence of pyknotic apoptosis mimicking mitotic figures. Furthermore, prediction of prognosis based on histopathology varies, especially for ACs. We examined the presence of interobserver variation between 5 experienced pulmonary pathologists who reviewed 123 originally diagnosed pulmonary carcinoid cases. The tumors were subsequently redistributed over 3 groups: unanimously classified cases, consensus cases (4/5 pathologists rendered identical diagnosis), and disagreement cases (divergent diagnosis by ≥2 assessors). κ-values were calculated, and results were correlated with clinical follow-up and molecular data. When focusing on the 114/123 cases unanimously classified as pulmonary carcinoids, the interobserver agreement was only fair (κ=0.32). Of these 114 cases, 55% were unanimously classified, 25% reached consensus classification, and for 19% there was no consensus. ACs were significantly more often in the latter category (P=0.00038). The designation of TCs and ACs by ≥3 assessors was not associated with prognosis (P=0.11). However, when disagreement cases were allocated on the basis of Ki-67 proliferative index (<5%; ≥5%) or nuclear orthopedia homeobox immunostaining (+; -), correlation with prognosis improved significantly (P=0.00040 and 0.0024, respectively). In conclusion, there is a considerable interobserver variation in the histopathologic classification of lung carcinoids, in particular concerning ACs. Additional immunomarkers such as Ki-67 or orthopedia homeobox may improve classification and prediction of prognosis.

On July 31, 2013, the Prostate Cancer Foundation assembled a working committee on the molecular biology and pathologic classification of neuroendocrine (NE) differentiation in prostate cancer. New clinical and molecular data emerging from prostate cancers treated by contemporary androgen deprivation therapies, as well as primary lesions, have highlighted the need for refinement of diagnostic terminology to encompass the full spectrum of NE differentiation. The classification system consists of: Usual prostate adenocarcinoma with NE differentiation; 2) Adenocarcinoma with Paneth cell NE differentiation; 3) Carcinoid tumor; 4) Small cell carcinoma; 5) Large cell NE carcinoma; and 5) Mixed NE carcinoma - acinar adenocarcinoma. The article also highlights "prostate carcinoma with overlapping features of small cell carcinoma and acinar adenocarcinoma" and "castrate-resistant prostate cancer with small cell cancer-like clinical presentation". It is envisioned that specific criteria associated with the refined diagnostic terminology will lead to clinically relevant pathologic diagnoses that will stimulate further clinical and molecular investigation and identification of appropriate targeted therapies.

Objective: To explore the diagnosis of rectal carcinoid tumors and to adopt the best method of treatment., Patients and Methods: A group of 312 cases of pathologically confirmed rectal carcinoid were analyzed retrospectively. Data were obtained retrospectively from a database of all colorectal malignancies at Qilu Hospital from January 2004 to December 2012. 4072 colorectal malignant tumors and 312 rectal carcinoid tumors were diagnosed. Endoscopic resection was performed on 44 patients, while the other 248 underwent anus partial extended radical polypectomy. We evaluated the clinical manifestations, diagnosis, treatment and follow-ups regarding carcinoids and the relation between tumor diameter and the rate of recurrence or metastasis after surgery., Results: There is no recurrence or metastasis after the transanal local resection in 284 cases with the tumor diameter less than 2 cm, 6 months to 7 years' follow-up. While, in 12 cases with the tumor diameter more than 2 cm radical surgery was performed, 8 cases had liver metastases at the time of the diagnosis of rectal carcinoid, 4 cases had no recurrence or metastasis after two and a half years' of follow ups, there is no recurrence or metastasis in 4 cases of multiple rectal carcinoids, whom all underwent radical surgery, follow ups continued for 2 years., Conclusion: Early diagnosis and treatment is important for rectal carcinoids, local resection is a simple, safe and effective treatment for carcinoids with a tumor diameter less than 2 cm., (Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.)

Background: The emergence of capsule endoscopy and double-balloon enteroscopy (DBE) has greatly enhanced the management of small bowel tumors (SBTs). DBE is particularly useful as a diagnostic modality because it allows for direct investigation of the gastrointestinal lumen, yet little data exist regarding its clinical efficacy., Aim: : To determine the diagnostic yield of DBE in detection of SBTs., Methods: We restrospectively reviewed our large prospectively collected DBE database from September 2005 to May 2012. Patients who were diagnosed with SBTs by DBE were included in the study. The diagnostic yield of DBE in detection of SBTs was calculated by frequency analysis., Results: A total of 1106 patients underwent 1652 DBE procedures. Of these patients, 134 (12.1%) were found to have an SBT. The majority (56.7%) of patients diagnosed with SBT were male, and the average age at the time of diagnosis was 64 years (SD±14 y). Indications for performing DBE included suspected mass lesion in 54.5% (73/134) of SBT patients, obscure gastrointestinal bleeding in 26.9% (36/134), and overt gastrointestinal bleeding in 14.9% (20/134). The most common SBTs identified were: carcinoid (26/134, 19.4%), hamartoma (14/134, 10.4%), inflammatory polyp (11/134, 8.2%), gastrointestinal stromal tumor (10/134, 7.5%), and lymphoma (10/134, 7.5%)., Conclusions: DBE is a valuable tool in the evaluation of SBTs. The incidence of SBTs in our patient population was significantly higher than the generally accepted incidence for the overall population, but was comparable with other similar studies. Carcinoid tumor was the most common SBT identified, and was most often seen in the ileum.

Background: Endoscopic mucosal resection (EMR) has been the endoscopic treatment of choice for rectal carcinoid tumors <10 mm in size. Endoscopic submucosal dissection (ESD) may cause more severe complications, longer operation time, and higher cost than EMR., Aim: : To compare EMR using band ligation (EMR-B) method with ESD for the endoscopic treatment of rectal carcinoid tumors., Methods: From November 2008 to September 2011, we enrolled consecutive patients with rectal carcinoid tumors <10 mm in diameter and without lymph node enlargement. Rate of complete resection rate, incidence of complications, and length of procedures were evaluated., Results: Sixty patients were enrolled (31 ESD cases and 29 EMR-B cases). The mean age was 48.03±13.09 years. Both groups had similar mean tumor diameter (EMR-B 4.34±1.75 vs. ESD 5.22±2.09 mm; P=0.084). Resection time was longer in the ESD group than in the EMR-B group (15.09±5.73 vs. 6.37±5.52 min; P<0.001). The complete resection rate was 80.6% (25 of 31) in the ESD group and 82.8% (24 of 29) in the EMR-B group (P=0.833). In incomplete resection cases, neither local recurrence nor distant metastasis was detected during the follow-up period., Conclusions: Compared with ESD, EMR-B resulted in a comparable histologically complete resection rate and took less time to perform. Given the advantages of easier and shorter procedure time, EMR-B may be considered the treatment of choice for small rectal carcinoid tumors.

Neuroendocrine tumors are uncommon in the female genital tract and have been described in the ovary, uterus, cervix, and vagina. Primary carcinoid tumors have not been described in the vulva. We report 3 cases in 3 middle-aged women who presented with a solitary vulvar nodule without any other associated symptoms. All were treated with simple local excision. Two tumors were composed exclusively of clear cells arranged in nests separated by fibrovascular septae. The third tumor predominantly exhibited nests of eosinophilic granular cells with scattered areas of cells showing clear cytoplasm. Immunohistochemical staining for chromogranin and neuron-specific enolase confirmed neuroendocrine differentiation in all cases. Follow-up of 5.5 to 16 years showed no evidence of recurrence or metastasis. Primary clear cell carcinoid tumors of the vulva need to be considered in the differential diagnosis of vulvar masses with clear cell features. Immunohistochemistry plays an important role in the diagnosis of these lesions.

Composite intestinal adenoma and microcarcinoid is a rare intestinal neoplasm consisting of intermingled adenomatous and well-differentiated neuroendocrine components. A few case reports and small series have suggested an indolent clinical course for this entity. We reported 7 cases of composite intestinal adenoma-microcarcinoid, including their morphologic features and clinical follow-up, both in biopsy and resection specimens. We identified 7 cases of composite intestinal adenoma-microcarcinoid from our pathology database. Five were from the large intestine, and 2 were in the duodenum. Morphologically, all microcarcinoids exhibited low-grade cytologic atypia and were devoid of significant pleomorphism, necrosis, and mitotic activity. Among the 7 lesions, 6 had a lobular architecture with smooth borders and mucosa-confined microcarcinoids; none had neuroendocrine carcinoma in subsequent resections. However, 1 colonic case had carcinoid cells penetrating the muscularis mucosae into the submucosa with an infiltrative border, and the resection showed metastatic high-grade neuroendocrine carcinoma in 1 lymph node. Composite intestinal adenoma-microcarcinoid is extremely rare. Although composite mucosa-confined adenoma-microcarcinoid is likely to have an indolent behavior, submucosal invasion by the neuroendocrine component may be associated with aggressive behavior.

Primary carcinoid tumors of the urinary bladder are exceedingly rare. Although they have been considered to be potentially malignant neuroendocrine neoplasms, some previously reported cases were associated with a carcinoma component that might have altered the outcome. Only 8 histologically well-documented cases of pure carcinoid tumors of the bladder and 1 of the prostatic urethra have been reported in the literature. In this study, we describe 6 additional primary pure carcinoid tumors arising in the bladder (5 cases) or prostatic urethra (1 case). Patients (4 male, 2 female) ranged in age from 45 to 60 years (average, 55 y) and presented with hematuria (n = 5 of 6), obstruction (n = 1 of 6), or for concurrent genitourinary disease (n = 1 of 6). All 6 cases shared gross and microscopic findings. Cystoscopic examination showed small, smooth surfaced, or polypoid nodules. The 5 cases in the bladder were all located within or near the trigone and bladder neck region. Microscopically, these 6 tumors were subepithelial and confined within the lamina propria, associated with adjacent cystitis cystica et glandularis. The tumors were composed of uniform, cuboidal, or columnar cells with finely stippled chromatin and inconspicuous nucleoli in a prominent pseudoglandular pattern composed of acinar and cribriform structures. The cells had moderate-to-abundant cytoplasm and basally located Paneth cell-like eosinophilic granules. Although occasional atypical cells with prominent nucleoli could be seen, mitotic activity was absent or rare and cases lacked necrosis. Neuroendocrine differentiation was confirmed by immunohistochemistry in all 6 cases. All tumors were completely excised by biopsies. There was no evidence of disease recurrence or progression in all 6 patients, including 3 patients who had clinical follow-up for >4 years. Primary pure carcinoid tumors of the urinary bladder (and prostatic urethra) have distinct pathologic characteristics, with their prominent pseudoglandular features leading to difficulty in diagnosis. They are likely to have a very favorable clinical outcome, and should be distinguished from mixed carcinoid tumors or urothelial carcinomas with neuroendocrine differentiation that show focal carcinoid-like histologic features.

Carcinoid metastases in the liver are typically solid, hypervascular lesions. We report 3 cases of cystic carcinoid tumors in the liver with radiographic findings. Two were metastatic from primary carcinoid tumors of the small intestine and one was not associated with any extra hepatic lesion at presentation or during 5 years of subsequent follow-up.

Carcinoid tumors are the most common neoplasms of the appendix. Histologically they have been categorized as classical, tubular, or goblet cell types. Goblet cell carcinoid has been regarded as a distinctive tumor type, not related to classic carcinoids, and to our knowledge combinations of these 2 tumor types have not been described in detail. In this report, we describe 5 cases of combined classical carcinoid and goblet cell carcinoid (GCC) tumors of the appendix. Four men and 1 woman, (mean age 53.4 y) presented with acute appendicitis (4 cases), whereas 1 presented with a pelvic mass owing to widespread pelvic disseminated disease. The tumors (0.6 to 6.0 cm) were located in the mid-portion and the tip of the appendix. Four patients were treated with right hemicolectomies (the patient with disseminated pelvic and ovarian metastases also had a pelvic exenteration), and 1 was treated with an appendectomy only. Four patients are alive and asymptomatic, whereas the patient with disseminated pelvic disease died 6 months after surgery. All 5 appendiceal tumors had microscopic features of both classical carcinoid and GCC, either intimately admixed or separate but closely apposed. The extent of the 2 components varied, with classical carcinoid representing 60% to 90% of the tumor. Both components stained for the general neuroendocrine markers, however, staining in the classic component was greater. The Mib-1 proliferation index varied from 1-15%, again with higher Mib-1 indices seen in the GCC component of all 5 cases. The pelvic soft tissue and ovarian metastases in case 4 consisted predominantly of a signet ring cell carcinoma with a minor component of goblet cells and was interpreted as an adenocarcinoma ex-GCC. In view of the fact that these combined carcinoid tumors appear to behave more as goblet cell carcinoids, detailed microscopic examination of classical carcinoid tumors of the appendix is suggested and larger series with longer follow-up is required to ascertain the true biologic potential of this unique form of combined carcinoid tumor of the appendix. The occurrence of both carcinoid types in the same appendices suggests a closer histogenetic relationship than previously believed, although the possibility that the 2 components represent separate, independent primaries ("collision tumors") can also be considered.

PAX (paired box) genes encode a family of transcription factors that regulate organogenesis and cell-lineage specification in multiple organ systems. In the pancreas, PAX proteins play a critical role in islet cell differentiation. We recently observed that islet cells show strong, diffuse staining for PAX8 by immunohistochemistry. However, PAX8 expression has not previously been examined in pancreatic endocrine tumors (PETs). The purpose of this study was to evaluate PAX8 expression in PETs, and to correlate expression with clinical and pathologic features and behavior. PAX8 expression in other well-differentiated neuroendocrine tumors (WDNETs) was also studied. In total, 190 tumors were evaluated: 156 primary WDNETs (63 PETs, 31 ileal, 5 duodenal, 5 gastric, 19 appendiceal, 13 rectal, and 20 pulmonary carcinoid tumors) and 34 liver metastases (18 PETs and 16 ileal carcinoid tumors). PAX8 was positive in 42/63 (67%) primary PETs. Expression of PAX8 was significantly associated with WHO category 1.1 ("benign" behavior) compared with category 1.2 (uncertain behavior) or 2 (well-differentiated endocrine carcinoma) (positive in 100%, 64%, and 52% of tumors, respectively; P<0.05). PAX8-positive PETs were also significantly smaller and more often clinically functional; PAX8-negative tumors were more frequently associated with liver metastases. PAX8 expression was not associated with patient age, gender, MIB1 index, or lymph node metastases. PAX8 expression was detected in 0/20 (0%) pulmonary, 1/5 (20%) gastric, 5/5 (100%) duodenal, 0/31 (0%) ileal, 4/19 (21%) appendiceal, and 11/13 (85%) rectal carcinoid tumors. Among the liver metastases, PAX8 was positive in 9/18 (50%) metastatic PETs compared with 0/16 (0%) metastatic ileal carcinoid tumors. In summary, PAX8 is expressed in normal pancreatic islet cells and in a high proportion of primary and metastatic PETs. In the GI tract, PAX8 is positive in the majority of duodenal and rectal carcinoid tumors, and in a minor subset of appendiceal and gastric carcinoids. PAX8 expression is absent in ileal and pulmonary carcinoid tumors. PAX8 immunostaining may be helpful in determining the primary site for a WDNET metastatic to the liver, as ileal (PAX8 negative) and pancreatic (PAX8 positive) tumors most often present as a metastasis from an occult primary. PAX8 may also be a prognostic marker in PETs, as loss of expression is associated with malignant behavior.

Testicular carcinoid tumors are rare with only limited studies. We identified 29 primary testicular carcinoid cases from 7 academic institutions. Patients ranged in age from 12 to 65 years old (mean 36). The most common presenting symptom was the sole finding of either a testicular mass or swelling seen in 15/24 cases with available information. The next most common mode of presentation was as an incidental finding seen in 6 cases. Two patients had carcinoid syndrome including diarrhea, hot flashes, and palpitations. Nineteen were pure carcinoid tumors, 3 were associated with cystic teratoma, 2 with cysts lacking epithelial lining, 4 with epidermoid cyst, and 1 with dermoid cyst. The mean size was 2.5 cm. All 29 primary carcinoids lacked associated intratubular germ cell neoplasia, unclassified type. Mitotic figures were rare in primary carcinoid tumors with only 3 cases showing more than 2 per 10 HPF; necrosis was found in only 1 case. Random scattered mild to moderate nuclear atypia was seen in 12/29 cases. Of the 28 cases found premortem, treatment included focal excision in 3 patients and radical orchiectomy in 25 patients. Follow-up, available in 24 cases, ranged from 1 to 228 months (mean 52.7 mo); of the 20 patients with testicular typical carcinoid tumors found premortem, all were alive at last follow-up without recurrences or metastases. Of the 4 patients with a primary atypical carcinoid tumor, 1 at the time of diagnosis had retroperitoneal and lung metastases who after chemotherapy underwent resection of the retroperitoneal tumor showing metastatic yolk sac tumor and embryonal carcinoma. After resection, serum AFP levels remained elevated and the patient is scheduled for salvage chemotherapy and bone marrow transplant. The other 2 patients with atypical carcinoid and follow-up had no evidence of disease at 68 and 114 months. Most primary carcinoid tumors of the testis have a benign clinical course even if associated with epidermoid/dermoid cysts, or histologically mature teratoma. However, lesions with the morphology of atypical carcinoid can occasionally exhibit metastatic spread.

The so-called clear cell change has been described in neuroendocrine tumors at several locations. Those associated with von Hippel Lindau disease are pathognomonically "clear" and the cytoplasmic appearance has been ascribed to intracytoplasmic lipid. However, lipid has not been demonstrated in all cases of clear cell carcinoid tumors. Such variants have not been described in carcinoid tumors of the appendix and cases with a prominent proportion of clear or more correctly, lipid-rich cytoplasm may bear a superficial resemblance to goblet cell carcinoid and/or signet ring adenocarcinoma. Seven cases, in 5 females and 2 males ranging in age from 22 to 65 years, were noted to have a population of lipid-rich and vacuolated clear cells accounting for 25% or more of the tumor population. The carcinoid tumors were incidental in all cases with 4 of patients presenting with appendicitis, 2 with concomitant mucinous cystadenocarcinomas of the appendix and 1 with an adenocarcinoma of the ascending colon. Morphologically, the tumors had a nested and trabecular pattern and were composed of an admixture of microvesicular and clear lipid-rich cells. There were no mitoses, areas of necrosis of lymphovascular invasion and all cases extended to the mesoappendix. All cases were positive for synaptophysin, chromogranin, and serotonin but negative for inhibin. Three cases were examined ultrastructurally, and showed the presence of intracytoplasmic lipid and neurosecretory granules. None of the patients have shown evidence of recurrent disease. The importance of recognizing this variant of carcinoid tumor in the appendix is to avoid confusion with goblet cell carcinoid tumors with or without a signet ring adenocarcinoma. The presence of multi-vacuolated, foamy and clear cells, some resembling signet ring or goblet cells, in otherwise classic carcinoid tumors is rare but should be considered in this context in the appendix.

Background: Metastatic carcinoid tumors (MCTs), an important subgroup of neuroendocrine tumors, occur infrequently and often have an indolent course, limiting data on long-term treatment outcomes. We aimed to assess treatment trends at a single center over time and the impact on the outcome., Study: Patients diagnosed with carcinoid tumors in the North West Adelaide Health Service between January 1, 1985 and March 1, 2007 were identified from the South Australian Cancer Registry., Results: We identified 92 patients with carcinoid tumors; 49 had MCT. Although treatment options increased over time, the most significant change was to access octreotide therapy, with 24 receiving long-acting somatostatin analogs. Survival improved over time and the median overall survival for patients receiving long-acting somatostatin analogs was 112 months compared with 53 months for those who did not (P=0.021, hazard ratio: 2.46). Ten year survival was 40% and 22%, respectively. About 75% of evaluable patients had a biochemical response to initial therapy and a measurable response occurred in 3 of 24 (13%) patients., Conclusions: This single center experience has provided insight into current treatment options for MCT, and suggests the use of long-acting somatostatin analogs may impact on disease control and survival. However, the uptake of other treatment options seems limited and there is a need for agents that target tumor progression.

Appendiceal tumors exhibiting both neuroendocrine and glandular differentiation are uncommon and have caused difficulty in pathologic classification, prediction of prognosis, and clinical management. Previously, such lesions have been variously designated as adenocarcinoid, goblet cell carcinoid (GCC), and mixed adenocarcinoma carcinoid. In this study, we undertook a retrospective investigation of 63 such cases and classified them as typical GCC (group A) and adenocarcinoma ex GCC on the basis of the histologic features of the tumor at the primary site. The adenocarcinoma ex GCC group was further divided into signet ring cell type (group B) and poorly differentiated adenocarcinoma type (group C). The clinical characteristics and prognosis were compared within these groups and with conventional de novo appendiceal adenocarcinomas. Both groups A and B tumors shared a similar immunoprofile, which included generally focal immunoreactivity for neuroendocrine markers, and a normal intestinal type mucin glycoprotein profile (negative MUC1 expression and preserved MUC2 immunoreactivity). The proliferative index was relatively low in these tumors and slightly increased from groups A to B tumors (11% to 16%). Both beta-catenin and E-cadherin exhibited a normal membranous staining pattern in groups A and B tumors. The poorly differentiated adenocarcinomas ex GCC (group C) demonstrated abnormal p53 and beta-catenin immunoreactivity. The mean follow-up time was 49+/-5 (SE) months. The overall disease-specific survival for all subtypes was 77%, with 46% of patients without evidence of disease and 31% alive with disease. The mean survival was 43+/-7 months. All the patients with clinical stage of I or IIA disease had a favorable outcome after appropriate surgery with or without chemotherapy. Although most patients (63%) with GCC presented at an advanced clinical stage, their clinical outcome could be differentiated by subclassification of tumors. The stage IV-matched 5-year survival was 100%, 38%, and 0% for groups A, B, and C, respectively. In conclusion, GCC is a distinctive appendiceal neoplasm that exhibits unique pathologic features and clinical behavior. They display a spectrum of histologic features and possess the potential to transform to an adenocarcinoma phenotype of either signet ring cell or poorly differentiated adenocarcinoma types. Careful evaluation of the morphologic features of GCCs and appropriate pathologic classification are crucial for clinical management and prediction of outcome. Surgical management with right hemicolectomy is recommended after appendectomy for most cases, particularly those with an adenocarcinoma component (groups B and C).

Goals: Our aim was to elucidate the incidence and distribution pattern of ghrelin-immunoreactive (IR) cells in various types of human gastric endocrine tumors, and their surrounding mucosa, and relate the findings to total ghrelin concentrations in plasma., Background: It has been demonstrated previously, that ghrelin-IR cells are present not only in normal human gastric oxyntic mucosa, but also in all types of enterochromaffinlike (ECL) cell carcinoids (ECL-CCs), and in mucosal regions affected by ECL cell hyperplasia., Study: Forty-eight gastric endocrine tumors were included in the study: 32 type I ECL-CCs, 3 type II, 9 type III, 1 non-ECL-CC, and 3 poorly differentiated endocrine carcinomas. The tumors were analyzed immunohistochemically with antibodies raised versus chromogranin A, synaptophysin, serotonin, somatostatin, vesicular monoamine transporter 2 and ghrelin. Total ghrelin in plasma was measured in 20 patients, using a commercial radioimmunoassay kit., Results: Ghrelin-IR cells were found in all types I and II ECL-CCs but in only a few cases of the other tumors. Ghrelin-IR cells were also found among the hyperplastic endocrine cells in the mucosa surrounding types I and II, where they showed diffuse, linear, nodular and adenomatoid hyperplasia patterns. In type III ECL-CCs and poorly differentiated endocrine carcinomas, only diffuse and linear ghrelin-IR cell hyperplasia was present in the oxyntic mucosa in about half of the cases, whereas the mucosa of the non-ECL-CC did not show this feature., Conclusions: Despite the frequent occurrence of ghrelin-IR cells in both the neoplastic parenchyma and the oxyntic mucosa, plasma total ghrelin concentrations remained within the reference range and can therefore not be used as a clinical marker to identify ghrelin expressing ECL-CCs or ghrelin cell hyperplasia.

We report the first case of a secondary tumor arising from a peritoneal nodule of mature teratoma in a patient with growing teratoma syndrome (GTS) of the ovary. The patient originally presented 19 years ago with an immature teratoma of the ovary and positive retroperitoneal lymph nodes. After surgery and chemotherapy, mature teratomas recurred as abdominal and pelvic masses after 1, 6, and 19 years. Upon the last recurrence, a trabecular carcinoid tumor developed in a mature teratoma associated with the liver. This case illustrates the importance of long-term follow-up for patients with GTS of the ovary, where the recurrent masses can appear many years after the primary tumor, compress the abdominal and pelvic structures and give rise to secondary neoplasms. In addition, we present a literature review of GTS of the ovary and some novel observations about this entity. On the basis of our review of ovarian GTS cases in the literature, we have found that ovarian GTS nodules tend to appear for the first time within 2 years of the initial primary. They remain confined almost exclusively to the pelvis, abdomen, and the retroperitoneum and do not venture to distant systemic sites. This new information may help identify and screen women with germ cell tumors of the ovary at risk for GTS.

Renal carcinoid tumors are exceedingly rare tumors that have been primarily documented as case reports in the literature. In this study, we report a series of 21 renal carcinoid tumors, with emphasis on histopathologic features and clinical outcomes. Patient age ranged from 27 to 78 years (average 52 y). The majority of specimens consisted of radical nephrectomies with or without associated lymph node dissection. Nine tumors were present in the left kidney and 10 were present in the right; location was not available for 2 specimens. No anatomic region of the kidney appeared to be preferentially involved. Twenty tumors were unifocal and ranged in size from 2.6 to 17 cm (average 6.4 cm), and 1 tumor presented as 2 nodules measuring 1 and 2.8 cm. Four patients had a documented history of a horseshoe kidney. Two patients had a history of renal calculi and 1 patient had a history of urothelial carcinoma 8 years prior. Presenting symptoms and clinical findings included back or flank pain (n=6/9), enlarging abdominal mass or fullness (n=2/9), hematuria (n=2/9), and anemia (n=1/9). Twelve patients had concurrent metastases at the time of initial surgery to sites including lymph nodes (n=11/12), liver (n=5/12), bone (n=1/12), and lung (n=1/12). One additional patient developed subsequent metastases to the liver within 6 months of surgery. Examination of the specimens identified carcinoid tumor with a variety of patterns including tightly packed cords and trabeculae with minimal stroma (n=17/21), trabecular growth with prominent stroma (n=4/21), focal solid nests (n=4/21), focal glandlike lumina (n=4/21). The border between tumor and normal kidney was sharply defined in most cases (n=16/21), although focal infiltration was noted in 5/21 cases. Extracapsular extension was documented in 11/21 (52%) cases. Calcifications were present in 5/21 cases. Mitotic activity, measured as mitoses per 10 high-power fields, ranged from 0 to 2 in most cases, with 1 case demonstrating up to 4 mitotic figures per single high-power field. Necrosis was absent in all cases. Immunostains were frequently positive for synaptophysin (n=18/20), chromogranin (n=13/20), Cam5.2 (n=14/16), and vimentin (n=12/15). CK7 was focally positive in a small subset of cases (n=3/18) and CK20 was positive in 1 case. TTF-1 and WT-1 were negative in all cases examined. Clinical follow-up was available on 15 patients and ranged from 3 months to 11 years. One patient died of disease at 8 months after surgery and 1 patient died without disease at 11 years after surgery. Of the remaining patients, 7 patients were alive without disease and 6 patients were alive with disease. Additional metastases developed in 4 patients and included metastases to the liver and bone.

WT1, the Wilms tumor gene product, can be expressed in various tumors from different anatomic sites, including some types of ovarian tumors. Regarding the latter, most studies have focused on surface epithelial-stromal tumors in which serous carcinomas are usually positive and endometrioid carcinomas are negative. Very few studies have specifically investigated this marker in ovarian sex cord-stromal tumors; however, limited data in the literature suggest that WT1 may be frequently expressed in sex cord-stromal tumors. As pure Sertoli cell tumor can be in the histologic differential diagnosis of endometrioid tumors (particularly borderline tumor and carcinoma) and carcinoid, immunostaining for WT1 might be of diagnostic value. Immunohistochemical staining for WT1 was performed in 108 ovarian tumors: pure Sertoli cell tumor (n=26), endometrioid borderline tumor (n=25), classic well-differentiated endometrioid carcinoma (n=23), sertoliform endometrioid carcinoma (n=12), and carcinoid (n=22). Additionally, inhibin and calretinin immunostaining were performed in all cases of Sertoli cell tumor for purposes of comparing expression with WT1. Extent of immunostaining was scored on a 0 to 4+ semiquantitative scale, and immunohistochemical composite scores based on a combination of extent and intensity of immunostaining were calculated in positive cases (possible range, 1 to 12). Nuclear expression of WT1 was present in 96% of Sertoli cell tumors, 16% of endometrioid borderline tumors, 13% of classic well-differentiated endometrioid carcinomas, 25% of sertoliform endometrioid carcinomas, and 0% of carcinoids. In Sertoli cell tumors, expression was diffuse (>50% of positive cells) in all positive cases. When positive in the non-Sertoli cell tumors, the extent of expression tended to be focal to patchy (50% or less positive cells). In Sertoli cell tumors, inhibin and calretinin were expressed in 96% and 54% of cases, respectively. The extent of expression of inhibin tended to be diffuse, similar to WT1; however, the extent of immunostaining for calretinin tended to be focal to patchy. The immunohistochemical composite scores for WT1, inhibin, and calretinin were 11.2, 7.6, and 4.8, respectively. Coordinate patterns for the extent of expression of WT1, inhibin, and calretinin in pure Sertoli cell tumor showed that all 3 markers were positive in 54% of cases; however, 42% were positive for WT1 and inhibin but negative for calretinin. In cases positive for both WT1 and inhibin, expression of both markers was diffuse in 84% of cases, but WT1 was diffuse while inhibin was focal to patchy in 16% of cases. We conclude that ovarian Sertoli cell tumor should be added to the growing list of WT1-positive tumors. This marker is useful for the distinction of Sertoli cell tumor from endometrioid tumors and carcinoid. The diagnostic utility of WT1 in Sertoli cell tumor is similar to inhibin but better than that of calretinin.

We reviewed the clinicopathologic profile of a series of recently diagnosed sporadic duodenal gastrin-cell (G-cell) tumors. All cases were discovered incidentally and had a unique clinicopathologic profile: all 18 cases were gastrin-positive tumors located in the duodenal bulb, were small in size (mean size 5.4 mm), demonstrated an insular architectural pattern, and were localized to the lamina propria and submucosa. None of the patients had Zollinger-Ellison or carcinoid syndrome. The behavior was indolent and there was no evidence of metastasis at diagnosis or during follow-up. In our sampled population, the presence of Helicobacter pylori gastritis and the use of proton pump inhibitors (PPIs) were significantly associated with the presence of G-cell tumors. Both the presence of H. pylori gastritis and use of PPI remained significant in a logistic regression model adjusted for age, race/ethnicity, and sex with P values of 0.0016 (odds ratio=10.1, 95% confidence interval: 2.3 to 42.4) and 0.008 (odds ratio=8.9, 95% confidence interval: 1.76 to 45.4), respectively. Most patients with tumors showed G-cell hyperplasia in the nontumorous regions of the duodenum. The high incidence of sporadic duodenal G-cell tumors in patients with H. pylori gastritis and long-term PPI use suggests an association that needs to be further explored. Presence of G-cell hyperplasia in the nontumorous duodenal mucosa suggests that these may originate from a proliferative phase, similar to the hyperplasia-dysplasia-neoplasia sequence seen in other endocrine tumors.

Composite adenoma-carcinoid tumors are rare colorectal lesions consisting of intermingled adenomatous and carcinoid components. Unlike other mixed endocrine-glandular colorectal neoplasms, which are generally malignant, their glandular component is histologically benign and their natural history is favorable. We present 4 cases of colonic adenomas containing microcarcinoids, a hitherto undescribed lesion that is either a precursor of composite adenoma-carcinoids or a related but independent entity. The cases, identified among our surgical and consultation files, were endoscopically routine sessile polyps removed from 4 otherwise normal individuals, 3 from the cecum and 1 from the distal colon. The microcarcinoids were 0.5 to 1.5 mm in size and situated within the basal lamina propria, where they interposed between the crypts and muscularis mucosae without disturbing the overall polyp architecture. Histologically, they consisted of collections of low-grade epithelial cells arranged in nests, cords, tubules, and irregular clusters and characterized by eosinophilic, granular, or clear cytoplasm and by round central nuclei with stippled or dusty chromatin. Endocrine differentiation of the microcarcinoids was confirmed by the expression of 3 or more of the following: Grimelius argyrophil, chromogranin, synaptophysin, neuron-specific enolase and somatostatin. No mitotic figures or MIB-1 or p53 positivity were observed. The glandular component of the polyps was unremarkable in 3 cases, but 1 polyp, in addition to a microcarcinoid, showed a diffuse pattern of mixed adenomatous-endocrine differentiation. The patients' clinical course was benign on the basis of 2 years' median follow-up (range, 6 mo to 10 y). Two patients with incomplete polypectomies underwent hemicolectomy revealing no residual endocrine neoplasia. Awareness of microcarcinoids in colonic adenomas should help avert potential diagnostic pitfalls posed by their pleomorphism, basal location, and infiltrative patterns, and may help clarify their natural history and possible relationship to composite glandular-carcinoid tumors.

We present, for the first time, two yolk sac tumors (YST) in women 37 and 18 years of age, one with a typical parietovisceral pattern and the other with a glandular pattern, which were associated with extensive areas of mucinous carcinoid (MC). The tumor in the first case had numerous nodules of tubulopapillary YST that merged with well-differentiated MC. This patient responded well to chemotherapy. The tumor in the second case consisted of an AFP-positive glandular YST, with a glandulopapillary pattern closely resembling fetal lung type adenocarcinoma, coexisting with an AFP-negative, cytokeratin 20-positive, atypical MC; transitional areas between the two components were also seen. In the material from the recurrences and metastases; however, no YST was present, the atypical MC having become the predominant component including areas that had become carcinomatous. There was a poor response to various chemotherapeutic regimens. AFP levels became negative during the course of disease paralleling the disappearance of the YST component and the overgrowth of an increasingly anaplastic MC. The patient died 1 year after diagnosis. We think that, in these cases, MC represented an unusual form of endodermal differentiation of the YST. It is important to differentiate the yolk sac and carcinoid components due to their different responses to chemotherapy and to evaluate the possibility of mucinous carcinoid developing into a highly aggressive carcinoma.

We describe a 54-year-old woman who had multiple gastric carcinoid tumors arising in the setting of marked hypergastrinemia associated with a lack of acid production by hypertrophic parietal cells. The serum gastrin level was 1,400 pg/mL, and investigation revealed no evidence for either of the recognized causes for hypergastrinemia-associated carcinoids, autoimmune gastritis, and Zollinger-Ellision syndrome. Partial gastrectomy was performed. Pathologic examination showed multiple intramucosal and invasive carcinoid tumors of the body and fundus in a background of marked ECL cell hyperplasia. There were no gastric or duodenal ulcerations. One perigastric lymph node was metastatically involved. The oxyntic mucosa showed marked hyperplasia and hypertrophy of the parietal cells. Some of these cells were vacuolated, and many displayed protrusions of apical cytoplasm into dilated oxyntic glands filled with inspissated eosinophilic material. Similar findings have occurred in 1 other patient, strongly indicating that the clinicopathologic alterations in the 2 cases are not random but, on the contrary, represent a very rare disorder of gastric carcinoids associated with an intrinsic acid secretion abnormality of the parietal cells.

PAX-5 is a B cell specific transcription factor crucial for B cell ontogeny and has been detected in most of human B-cell lymphomas. In mouse, PAX-5 is also highly expressed in the central nervous system under tight temporal and spatial controls during embryogenesis. In humans, however, detection of PAX-5 in cells other than B lymphocytes has rarely been reported. We have encountered cases of Merkel cell carcinoma expressing PAX-5 during our routine evaluation of lymphoma. Because Merkel cell carcinoma is a small blue round cell tumor constantly in the differential diagnosis of lymphoma, we expanded our study in an effort to determine if PAX-5 is significantly expressed in neuroendocrine tumors. Based on our immunohistochemistry results using a monoclonal anti-PAX5 antibody with paraffin-embedded tissue sections, we report herein that PAX-5 was detected in 29 of 31 (93.5%) of Merkel cell carcinoma and 22 of 30 (73.3%) of small cell carcinoma, but in none of 17 cases of carcinoid tumor. Furthermore, the staining intensity of PAX-5 in Merkel cell carcinoma was frequently comparable with that in most B-cell lymphomas. We conclude that expression of PAX-5 is not confined to the B cell lineage and is frequently associated with neuroendocrine carcinomas.

Seven patients with typical or atypical pulmonary carcinoid tumors overdiagnosed as small-cell carcinoma on bronchoscopic biopsies are described. Bronchial biopsies from 9 consecutive small-cell lung carcinoma patients were used as control group for histologic and immunohistochemical studies (cytokeratins, chromogranin A, synaptophysin, Ki-67 [MIB-1], and TTF-1). The carcinoid tumors presented as either central or peripheral lesions composed of tumor cells with granular, sometimes coarse chromatin pattern, high levels of chromogranin A/synaptophysin immunoreactivity, and low (<20%) Ki-67 (MIB-1) labeling index. The tumor stroma contained thin-walled blood vessels. Small-cell carcinomas always showed central tumor location, finely dispersed nuclear chromatin, lower levels of chromogranin A/synaptophysin, and high (>50%) Ki-67 (MIB-1) labeling index. The stroma contained thick-walled blood vessels with glomeruloid configuration. Judging from this study, overdiagnosis of carcinoid tumor as small-cell carcinoma in small crushed bronchial biopsies remains a significant potential problem in a worldwide sample of hospital settings. Careful evaluation of hematoxylin and eosin sections remains the most important tool for the differential diagnosis, with evaluation of tumor cell proliferation by Ki-67 (MIB-1) labeling index emerging from our review as the most useful ancillary technique for the distinction.

It is well known that small intestinal carcinoid tumors may occur as solitary or multiple lesions. However, the biologic significance of multiple carcinoid tumors has not been clearly defined. The purpose of this study was to compare the clinical and pathologic features and prognosis of patients with solitary versus multiple carcinoid tumors of the ileum. Sixty-eight patients, including 50 with solitary and 18 with multiple carcinoid tumors, were included in the study. Hematoxylin and eosin-stained slides from routinely processed tumor resection specimens of the ileum were evaluated for a variety of histologic features such as tumor size, depth of invasion, tumor stage, and venous, perineural, and lymphovascular invasion. Follow-up and clinical data, such as patient age, gender, presenting complaints, presence of synchronous or metachronous malignancies, and presence of the carcinoid syndrome, were obtained and the results were compared between the two patient groups. Fifty patients with solitary carcinoid tumors (male/female ratio, 27:23) and 18 patients with multiple tumors (male/female ratio, 7:11) were identified. Patients with multiple carcinoid tumors were significantly younger than patients with solitary tumors at the time of diagnosis (55 years vs 63 years, p = 0.006). There was a high association between multiple carcinoid tumors and the carcinoid syndrome (4 of 18 vs 1 of 50, p = 0.004) as compared with patients with solitary carcinoid tumors. There was also an association between tumor multiplicity and venous invasion, but this relationship was not statistically significant (p = 0.07). The follow-up period was similar for both groups (mean 36 months, median 26 months, range 1-139 months). A significantly higher proportion of patients with multiple carcinoid tumors were either alive with disease or died of disease (56%) compared with those with solitary carcinoid tumors (18%, p = 0.002), and this relationship persisted in multivariate analysis (p = 0.02). Overall, no significant differences were observed between these two patient groups with respect to other clinicopathologic features such as tumor size, depth of invasion, presence of distant metastases, lymphatic or perineural invasion, or presence of an associated malignancy (p >0.05). In conclusion, we found that patients with multiple carcinoid tumors are younger, have a significantly greater risk of developing the carcinoid syndrome, and have a poorer prognosis than patients with solitary tumors.

Several case reports have emphasized that esophageal carcinoid tumors are associated with a poor prognosis. To expand our knowledge about the pathology and biologic behavior of these rare tumors, we reviewed the clinicopathologic and immunohistochemical findings of four cases of primary esophageal carcinoid. The age of the patients ranged from 48 to 82 years (mean 63 years; median 61 years). The lower segment of the esophagus was involved in two cases and the mid segment was involved in one case. The sizes of the tumors ranged from 0.3 cm to 3.5 cm. Two tumors were confined to the lamina propria and two invaded into the muscular wall. Two tumors appeared polypoid, whereas the remaining two were incidental findings and associated with adenocarcinoma arising in a background of Barrett esophagus. The adenocarcinoma was superficially invasive in one case, whereas it penetrated the muscular wall in the other. All four carcinoid tumors were immunoreactive with chromogranin and synaptophysin. There was focal expression of serotonin in two cases, glucagon in one case, and pancreatic polypeptide in one case. Endocrine cell hyperplasia was noted in both the Barrett esophagus and the invasive adenocarcinoma. One patient died secondary to postoperative pneumonia. Three patients are alive and disease free at 1, 6, and 23 years status post therapy. None of the patients had metastatic disease. These findings show that esophageal carcinoids are associated with a favorable prognosis. They arise in two settings: (1) a single large polypoid tumor or (2) an incidental finding and in association with adenocarcinoma arising in the background of Barrett esophagus. The presence of endocrine cell hyperplasia in the Barrett mucosa and the adenocarcinoma supports the hypothesis that these lesions arise from a common stem cell.

Antibodies to six specific regions of the chromogranin A (CgA) molecule were used to study their immunoreactivity in human neuroendocrine (NE) tumors. Tissue specimens from endocrine pancreatic tumors (n = 14), duodenal carcinoids (n = 2), bronchial carcinoids (n = 5), ileal carcinoids (n = 5) appendix carcinoids (n = 2), medullary thyroid carcinomas (n = 6), parathyroid adenomas (n = 2), and pheochromocytomas (n = 8) were analyzed. The results showed that the NE tumor types expressed varying numbers of CgA fragments. A variation in frequency of the expression of immunoreactive cells was sometimes seen also within the same tumor type. The midportion fragment CgA 176-195 (chromacin) was the only fragment expressed in all tumors. Benign and malignant tumors expressed different patterns, being especially true of insulinomas and pheochromocytomas. These findings suggest that region-specific antibodies to CgA fragments can be used as a diagnostic tool for the characterization of NE tumors.

We describe a morphologically distinctive carcinoid tumor of the gallbladder that occurred in a 38-year-old man with von Hippel-Lindau (VHL) disease. The carcinoid tumor was composed predominantly of lipid-containing clear cells arranged in nests and tubules with pagetoid spread into the biliary epithelium and was interpreted as metastatic renal cell carcinoma. The neoplastic cells showed diffuse immunoreactivity for chromogranin, synaptophysin, cytokeratins (cytokeratin 7 and AE1/AE3) and, unexpectedly, for inhibin, but were negative for monoclonal carcinoembryonic antigen, serotonin and a variety of peptide hormones. This clear cell carcinoid tumor of the gallbladder was histologically similar to the recently described clear cell endocrine pancreatic tumor associated with VHL. Four cases of the latter tumor, which were also inhibin positive showed, in addition, focal and variable reactivity for the pancreatic hormones. Two classical carcinoid tumors of the gallbladder, two renal cell carcinomas associated with VHL and 11 of 13 sporadic endocrine pancreatic tumors (not associated with VHL) did not show immunoreactivity for inhibin. Inhibin appears to be an immunohistochemical marker for gallbladder clear cell carcinoid and clear cell endocrine pancreatic tumors associated with VHL and is a useful tool to distinguish these tumors from metastatic renal cell carcinoma. However, the basis for the inhibin positivity in these endocrine tumors is unknown.

Only rare primary mucinous (goblet cell) carcinoids of the ovary have been reported, and their clinicopathologic features have not been well delineated. The authors studied 17 examples from patients 14 to 74 years of age. The clinical presentations were similar to those of ovarian neoplasms in general. The tumors ranged from 0.8 to 30 cm in diameter. In six cases the tumor was in the wall of a mature cystic teratoma, appearing grossly as solid nodules or areas of thickening in four of them, six tumors were entirely solid, and five were solid associated with other types of cystic tumor. The tumors were divided into three groups on the basis of their microscopic features. Six neoplasms, designated "well differentiated," were composed of small glands, many of which floated in pools of mucin. The glands were lined by goblet cells and columnar cells, some of which were of neuroendocrine type. Three tumors, designated "atypical," were characterized by crowded glands, some of which were confluent, small islands with a cribriform pattern, and scattered microcystic glands. The glands were lined by cuboidal to columnar cells, some of them neuroendocrine, admixed with goblet cells. Eight tumors, designated "carcinoma arising in mucinous carcinoid," contained islands and larger nodules of tumor cells, or closely packed glands, as well as single cells, mainly of the signet ring cell type. Most of the cells were devoid of mucin and were severely atypical with marked mitotic activity. Necrosis was present in all eight tumors. Seven of the eight tumors with a carcinomatous component contained at least minor foci of well-differentiated mucinous carcinoid; the eighth contained only foci of atypical mucinous carcinoid. The neuroendocrine nature of a variable proportion of the cells in all three groups was demonstrated by staining for neuroendocrine markers. The mucinous nature of other cells was confirmed by mucicarmine or Alcian blue stains. The ovary contained an intrinsic component of trabecular and insular carcinoid, and of strumal carcinoid in one case each, an adjacent mature cystic teratoma in six cases, mucinous cystadenocarcinoma in three cases, and borderline mucinous cystic tumor, borderline Brenner tumor, and epidermoid cyst in one case each. Fifteen tumors were stage I, one was stage II, and one was stage III. The last two tumors had a carcinomatous component. Follow-up data were available for 15 patients; 12 were alive and free of tumor 2.3 to 14 years (average, 4.7 years) after the ovarian tumor was excised. One patient, whose tumor had a carcinomatous component, died 3 years postoperatively of unrelated causes. Two patients, both of whom had a carcinomatous component in their tumor, died 9 and 12 months postoperatively. Primary mucinous carcinoids must be distinguished from metastatic mucinous carcinoid tumors from the appendix or elsewhere. Features supporting an ovarian origin are the additional presence in the specimen of teratoma or an ovarian surface epithelial tumor, an absence of blood vessel or lymphatic space invasion, and confinement to a single ovary. Similar features help to distinguish mucinous carcinoids from Krukenberg tumors. Mucinous carcinoids should also be distinguished from strumal carcinoids, which can contain mucinous glands, and insular carcinoid tumors that arise rarely in the wall of a mucinous cystic neoplasm. Although the number of cases in this series is small, the follow-up data suggest that the degree of differentiation, particularly the presence of frank carcinoma, is an important prognostic factor.

The authors report seven patients with carcinoid tumors of the extrahepatic bile ducts (EHBDs). All patients were women, with an average age at diagnosis of 49.8 years (range, 37-67 yrs). The most common presenting symptom was painless jaundice with or without pruritus. Although one patient had peptic ulcer disease before the onset of obstructive jaundice, none had systemic endocrine manifestations. These neoplasms were most often located in the common bile duct. Grossly, the carcinoid tumors were usually nodular and poorly demarcated, and ranged from 1.1 to 2.7 cm in size. Only one of the neoplasms was polypoid. Microscopically, the tumors had a trabecular or nesting pattern with occasional tubule formation, and were composed of relatively small cells with granular chromatin. All of the neoplasms expressed chromogranin and two expressed synaptophysin. Three expressed serotonin and two of the three were also immunoreactive for pancreatic polypeptide or somatostatin. Two tumors were focally positive for gastrin and one of these two tumors was also positive for serotonin and pancreatic polypeptide. All seven carcinoid tumors showed no immunoreactivity for p53, and assays for p53 loss of heterozygosity analysis were negative in two, suggesting that p53 mutations do not play a role in the pathogenesis of EHBD carcinoids. A mutation in codon 12 of K-ras was found in one carcinoid tumor whereas two of two showed immunoreactivity for Dpc4 protein. In view of the small number of carcinoids studied, the importance of these findings in the pathogenesis of these tumors is unclear. Ultrastructural examination of three of the tumors revealed numerous membrane-bound, round neurosecretory granules. Clinically, these lesions had an indolent course. Even in the presence of lymph node metastases (noted in two patients), all of the patients remained disease free 2 to 11 years (average follow up, 6.6 yrs) after segmental resection or pancreaticoduodenectomy (Whipple's procedure). Because carcinoid tumors of the EHBD are of low malignant potential, they should be separated from the more common adenocarcinomas in this location.

Clinical findings and surgical treatment of a 68 years old man with carcinoid tumor of Meckel's diverticulum are reported. Carcinoids in Meckel's diverticula are rare tumors, commonly discovered incidentally during surgical procedures for different indications. Symptoms are frequently expression of a metastatic disease. Specific diagnostic and therapeutic tools are discussed.

The association between gastric carcinoid tumors and pernicious anemia is well recognized. Such tumors occur in the presence of achlorhydria, chronic atrophic gastritis, hypergastrinemia, and enterochromaffin-like cell hyperplasia. In this case report, a 29-year-old woman with pernicious anemia and autoimmune thrombocytopenia who developed gastric carcinoid tumors of the gastric body is described. This is the second description of pernicious anemia associated with autoimmune thrombocytopenia. This association in a young woman together with the therapeutic options and decisions that were taken in the treatment of the patient are discussed.

A 62-year-old man with a history of a resected rectal polyp was diagnosed 14 years later with right liver and multiple bone metastases. The liver biopsy showed a malignant epithelial tumor that was positive for neuron-specific enolase immunostaining and negative for chromogranin. Electron microscopy was characteristic of that for an endocrine tumor. Most circulating hormonal peptide levels were within normal ranges and only motilin level was elevated. On the right hepatectomy, the three large metastases had a histologic picture suggestive of an endocrine tumor. Immunohistochemistry revealed in some areas numerous tumor cells expressing motilin, and a few cells were strongly positive for pancreatic polypeptide and somatostatin. The retrospective analysis of the rectal polyp showed a similar histology and immunohistochemical profile, indicating that this lesion was the primary tumor. Motilin-positive cells from one of the hepatic lesions were identified on semithin sections and further processed for electron microscopy. Neurosecretory granules were numerous in all cells. Immunoelectron localization enabled us to characterize the motilin-containing neurosecretory granules, which had a mean diameter of 168.3x38.1 nm. Although not all tumor cells were motilin-positive, a diagnosis of motilinoma for the rectal polyp and its hepatic and bone metastases was proposed.

Neural cell adhesion molecules (NCAM) represent specific markers of neuroendocrine (NE) differentiation in lung cancer. Because the polysialic acid form (NCAM-PSA) has reduced adhesion properties, we hypothesized that NCAM-PSA expression could favor metastatic spread. Immunostaining of NCAM and NCAM-PSA were therefore compared in 120 NE lung tumors, including 17 typical carcinoids, 3 atypical carcinoids, 30 large cell NE carcinomas and 70 small cell lung carcinomas, as compared with 25 adenocarcinomas and 25 squamous cell carcinomas. Neural cell adhesion molecules were negative in adenocarcinomas and squamous cell carcinomas but were constantly expressed in all NE tumors from typical carcinoids to small cell lung carcinomas. NCAM-PSA expression was significantly more frequent in high-grade tumors, with 24 of 30 positive cases in large cell NE carcinomas and 65 of 70 positive cases in small cell lung carcinoma, than in carcinoids with 10 of 17 and 2 of 3 positive cases in typical carcinoids and atypical carcinoids, respectively. The neural cell adhesion molecule-polysialic acid form scores of staining were significantly higher in high-grade as compared with low-grade tumors (p = 0.002), and were correlated with nodal spread (p = 0.04) and metastasis (p = 0.016) across histologic classes but not in individual tumor type. We conclude that NCAM-PSA connotes poor differentiation and aggressive clinical behavior in the spectrum of NE lung tumors, but cannot be regarded as a prognostic factor in individual tumor classes.

A clear cell variant of primary pulmonary carcinoid tumor is described. The tumor arose in a 53-year-old woman who was incidentally found to have a solitary pulmonary nodule in the left upper lobe during routine chest roentgenography. Histologically, the tumor was composed of predominantly clear to lightly eosinophilic, polygonal cells with bland nuclei arranged in sheets and nests. Nuclear pleomorphism, necrosis, vascular invasion, and mitotic figures were not seen. The tumor cells were negative for oil-red-O and periodic acid-Schiff stains with and without diastase pretreatment on frozen and formalin-fixed sections, respectively. During immunohistochemical evaluation, the tumor cells were focally positive for cytokeratin and diffusely positive for neuron-specific enolase and chromogranin. Electron microscopy performed on paraffin block-retrieved tissue showed the presence of electron-dense, neurosecretory-type granules and variably sized vacuolated areas within the cytoplasm. the nature of which remained unclear. Intracytoplasmic glycogen or lipid were not identified. To our knowledge, this is the first report of pulmonary clear cell carcinoid tumor.