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Steroid cell tumors (SCTs) of the ovary are rare and understudied, and as such, uncertainties remain about their malignant potential, as well as clinicopathologic predictors of patient outcome. Based on a multi-institutional cohort of cases, we present findings from the largest study of SCT reported to date. Clinicopathologic data were documented on 115 cases of SCT that were assembled from 17 institutions. The median patient age was 55 years (range: 9 to 84). When measured, preoperative androgen levels were elevated in 84.2% (48/57) of patients. A total of 111 (96.5%) cases were classified as stage I (103 stage IA; 2 stage IB; 6 stage IC). The stage distribution for the remaining 4 patients was as follows: stage II (n = 1), III (n = 3; 1 IIIA, 1 IIIB, 1 IIIC). The median tumor size was 3 cm (range: 0.2 to 22). Cytologic atypia, microscopic tumor necrosis, microscopic tumor hemorrhage, and a mitotic index of >1 mitotic figure/10 high-power fields were present in 52% (60/115), 9.6% (11/115), 37% (43/115), and 19% (22/115) of cases, respectively. Of 115 patients, 7 (6.1%) recurred postexcision, 4 (3.5%) ultimately died of disease, and 10 (8.7%) either recurred, died of disease, or were advanced stage at presentation. The median duration to recurrence postresection was 33 months (range: 23 to 180). Four of the 7 recurrences were stage IA at baseline. Tumor size >4 cm, International Federation of Gynecology and Obstetrics (FIGO) stage ≥IB, tumor necrosis, and tumor hemorrhage were each significantly associated with reduced recurrence-free survival in log-rank tests and univariable Cox models, with age older than 65 years being of marginal significance (hazard ratio [HR]: 5.4, 95% CI: 1.0-30.0, P = 0.05). Multivariable analyses suggested that FIGO stage ≥IB (HR: 27.5, 95% CI: 2.6-290.5), and age older than >65 years (HR: 21.8, 95% CI: 1.6-303.9) were the only parameters that were independently associated with recurrence. Cross-section analyses showed that tumor necrosis, tumor hemorrhage, and larger tumor size were significantly associated with a FIGO stage ≥IB status, which bolstered the conclusion that they are not independent predictors of recurrence. In summary, <10% of SCTs are clinically malignant, a substantially lower frequency than has previously been reported in the literature. Clinicopathologic predictors of patient outcomes that are prospectively applicable in practice could not be definitively established. Recurrences may occur many years (up to 15 y in this study) after primary resection, even in stage IA cases., 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.)

Carcinosarcomas (CSs) of the endometrium are biphasic malignancies, composed of high-grade carcinomatous and sarcomatous components. Surgical stage and pathologic characteristics are the most important prognostic findings, with a 5-yr survival of 15% to 30% in advance stage disease. Folate receptor alpha (FRA) overexpression has been observed in endometrial carcinomas and not yet studied in CSs. This study evaluates semiquantitative expression of FRA in both carcinomatous and sarcomatous components of CSs on whole tissue sections. Immunohistochemistry for FRA expression was performed and extent and intensity of staining were recorded for each case for both histologic components. A total of 46 cases were stained for FRA. The majority of these (40/46, 87%) showed FRA staining at variable intensity in the carcinomatous component, stronger in serous carcinomas and high-grade endometrioid, while only a small subset of tumors demonstrated weak staining in the sarcomatous component (2/46, 4.35%). CS is known to be associated with poor prognosis and adjuvant therapy is recommended even in low stage disease. Serous and high-grade endometrioid carcinomas are the most common carcinomatous components of CSs and are known to show consistently high FRA expression. Folate plays a role in tumor cell migration and loss of cellular adhesion, which are key steps in epithelial-mesenchymal transition, the process by which CS develops from carcinoma cells. Our study shows expression of FRA in the carcinomatous component of almost all CS cases (87%), further favoring FRA as a target for adjuvant treatment. While expression of FRA in the sarcomatous component was rarely observed, the carcinomatous component being associated with metastatic potential underscores the importance of anti-FRA therapy for systemic disease control., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 by the International Society of Gynecological Pathologists.)

Immunohistochemistry (IHC) for mismatch repair (MMR) proteins is recommended in endometrial carcinomas as a screening test for Lynch syndrome, and mismatch repair deficiency (MMRd) is reported in ∼30% of cases. However, few studies have evaluated the rate of MMR loss in uterine carcinosarcomas. A 5-year retrospective database search of uterine carcinosarcomas was performed at 3 academic institutions. The histologic diagnoses, type of carcinoma present, and MMR IHC interpretations were confirmed by a gynecologic pathologist. One hundred three cases of uterine carcinosarcomas with available MMR IHC results were identified. Ninety-nine cases (96%) showed intact expression and 4 cases (4%) showed loss of MLH1/PMS2. All MMRd carcinosarcomas identified in this series had an endometrioid carcinomatous component and wild-type p53 expression. In contrast, the majority of MMR intact carcinosarcomas had a serous morphology and aberrant p53 expression. Three additional cases initially diagnosed as carcinosarcoma also revealed MMRd; however, given the lack of clear mesenchymal differentiation, these cases were reclassified as dedifferentiated endometrial carcinomas and were subsequently excluded from the carcinosarcoma category. No cases of Lynch syndrome were identified among carcinosarcoma patients, as all 4 MMRd cases were due to somatic MLH1 hypermethylation. In summary, we found that the rate of MMRd is markedly lower in uterine carcinosarcoma when compared with endometrial carcinoma. In the setting of MMR loss, a diagnosis of dedifferentiated carcinoma should be considered as almost half of the MMRd tumors which were called carcinosarcomas initially were reclassified as dedifferentiated on review. However, given the interobserver variability in the classification of carcinosarcoma versus dedifferentiated carcinoma a universal screening approach that includes uterine carcinosarcoma is still recommended.

DICER1 mutations (somatic or germline) are associated with a variety of uncommon neoplasms including cervical and genitourinary embryonal rhabdomyosarcoma (ERMS). We report a primary ovarian and 2 primary fallopian tube ERMS occurring in 60-, 13-, and 14-year-olds, respectively. The 3 neoplasms exhibited a similar morphologic appearance being polypoid and containing edematous hypocellular areas and hypercellular foci composed of small cells with scant cytoplasm exhibiting rhabdomyoblastic differentiation (desmin, myogenin, myoD1 positive). There was cellular cartilage in all cases and extensive foci of anaplasia, eosinophilic globules, and bone/osteoid in 1 case each. All 3 neoplasms exhibited DICER1 mutations; in 1 of the tubal cases, the patient had a germline mutation and in the other 2 cases, the DICER1 mutations were somatic. Accompanying DICER1 "second hits" were identified in all cases. In 2 of the neoplasms, SALL4-positive glandular structures were present which we speculate may represent an unusual primitive "metaplastic" phenomenon. Our study adds to the literature on ERMS at unusual sites associated with DICER1 mutations. ERMS arising at such sites, especially when they contain cartilage or bone/osteoid, are especially likely to be associated with DICER1 mutations. Pathologists should be aware of this as these may be the sentinel neoplasms in patients with DICER1 syndrome and confirming a germline mutation can facilitate the screening of the individual and affected family members for other neoplasms which occur in this syndrome.

Background & Aims: The intestinal epithelium must be resilient to physiochemical stress to uphold the physiological barrier separating the systemic compartment from the microbial and antigenic components of the gut lumen. Identifying proteins that mediate protection and enhancing their expression is therefore a clear approach to promote intestinal health. We previously reported that oral ingestion of the probiotic Lactobacillus rhamnosus GG not only induced the expression of several recognized cytoprotective factors in the murine colon, but also many genes with no previously described function, including the gene encoding proline-rich acidic protein 1 (PRAP1). PRAP1 is a highly expressed protein in the epithelium of the gastrointestinal tract and we sought to define its function in this tissue., Methods: Purified preparations of recombinant PRAP1 were analyzed biochemically and PRAP1 antisera were used to visualize localization in tissues. Prap1 -/- mice were characterized at baseline and challenged with total body irradiation, then enteroids were generated to recapitulate the irradiation challenge ex vivo., Results: PRAP1 is a 17-kilodalton intrinsically disordered protein with no recognizable sequence homology. PRAP1 expression levels were high in the epithelia of the small intestine. Although Prap1 -/- mice presented only mild phenotypes at baseline, they were highly susceptible to intestinal injury upon challenge. After irradiation, the Prap1 -/- mice showed accelerated death with a significant increase in apoptosis and p21 expression in the small intestinal epithelium., Conclusions: PRAP1 is an intrinsically disordered protein highly expressed by the gastrointestinal epithelium and functions at exposed surfaces to protect the barrier from oxidative insult., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Uterine yolk sac tumors have gained increased recognition in recent years. The current study is a multi-faceted examination of yolk sac tumor-like phenotypes in endometrial tumors, based on an analysis of 3 groups of uterine tumors: Group 1: 9 endometrial tumors that had been classified as yolk sac tumor, or as having a yolk sac tumor component, were assessed with a 35-marker immunohistochemical panel, with the goal of defining their immunophenotypic spectrum; Group 2, comprised of 70 endometrial carcinomas of various histotypes, were analyzed for their expression of SALL4, Glypican-3, and AFP, to assess the specificity of these markers for yolk sac tumors relative to endometrial carcinomas; Group 3, comprised of 626 archived cases of endometrial carcinoma/carcinosarcoma, reviewed to define the frequency of yolk sac tumor-like morphology therein. Yolk sac tumor areas in the Group 1 cases were consistently immunoreactive for SALL4 and Glypican-3; variably positive for AFP (89%), Villin (89%), PLAP (78%), 34βE12 (67%), CAM 5.2 (62.5%), EMA (56%), CD117 (50%), p16 (50%), CDX2 (44%), p53 (44% aberrant), MOC31 (37.5%), CK7 (33%), GATA3 (33%), CK5 (25%), and PAX8 (11%); and were negative for CD30, Napsin A, OCT4, estrogen, androgen, and progesterone receptors. 29 (41%) of the 70 group-2 cases expressed at least one of the 3 markers, and 96% of the positive cases was a high-grade histotype. Glypican-3, SALL4, and AFP were positive in 30, 20, and 2.8% of group-2 cases respectively; however, co-expression of any 2, or all 3 markers was uncommon (<9 and 1.4% of cases respectively). Potential yolk sac tumor-like morphology was identified in 5 (0.8%) of 626 group-3 cases, and three were ultimately deemed to be true yolk sac tumor phenotypes based on their morphologic and immunophenotypic similarity to the group 1 cases. These findings highlight the broad immunophenotypic spectrum of uterine yolk sac tumors, the potential pitfalls associated with using immunophenotypes alone to define yolk sac tumor differentiation in endometrial carcinoma, and the utility and limitations of morphologic assessment to identify yolk sac tumors at this site.

GATA binding protein 3 (GATA3) immunohistochemistry is primarily used as a marker of breast and urothelial differentiation, particularly in metastatic settings. In the gynecologic tract it also serves a robust marker for mesonephric and trophoblastic tumors. However, expression has also been described in more common malignancies of gynecologic tract including ovarian, endometrial, and cervical carcinomas. Data on the distribution of GATA3 expression in gynecologic malignancies is somewhat limited, particularly across different histologic subtypes of ovarian, endometrial, and cervical carcinomas. To assess the rates of GATA3 expression among common gynecologic cancers of various histologic types, 100 ovarian carcinomas, 64 endometrial carcinomas/atypical hyperplasias, 16 cervical squamous cell carcinomas (SCCs), and 14 endocervical adenocarcinomas were evaluated by immunohistochemistry for GATA3 positivity. Eight percent of endometrial carcinomas expressed GATA3, including 2 serous carcinomas, 1 carcinosarcoma, and 1 case of atypical hyperplasia. Six percent of ovarian carcinomas were GATA3-positive including 2 clear cell carcinomas, 2 mucinous adenocarcinomas, and 2 high-grade serous carcinomas. Thirty-eight percent of cervical SCCs showed weak to moderate staining in up to 50% of tumor cells. All endocervical adenocarcinomas were entirely negative for GATA3. In summary, GATA3 shows focal weak to moderate expression in a subset of endometrial and ovarian carcinomas. In contrast, usual-type endocervical adenocarcinomas are typically negative for GATA3, which can be helpful in differentiating them from mesonephric proliferations or carcinomas. A larger proportion of cervical SCCs express GATA3, therefore caution should be exercised when using this stain in the setting of a lower genitourinary carcinomas.

Ovarian sex cord-stromal tumors are uncommon tumors and clinically differ from epithelial tumors. They occur across a wide age range and patients often present with hormone-related symptoms. Most are associated with an indolent clinical course. Sex cord-stromal tumors are classified into 3 main categories: pure stromal tumors, pure sex cord tumors, and mixed sex cord-stromal tumors. The rarity, overlapping histomorphology and immunoprofile of various sex cord-stromal tumors often contributes to diagnostic difficulties. This article describes the various types of ovarian sex cord-stromal tumors and includes practical approaches to differential diagnoses and updates in classification., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Endometrial clear cell carcinoma (ECCC) is an uncommon histotype without unique identified molecular alterations. Recently, The Cancer Genome Atlas molecular subtypes have been reported in ECCC. ECCC cases were collected from 11 institutions with diagnoses confirmed by morphologic review and immunohistochemistry. DNA mismatch repair (MMR) proteins, p53 expression, and ARID1A expression was assessed by immunohistochemistry on tissue microarrays. Targeted next-generation sequencing was completed for POLE, TP53, KRAS, and PIK3CA. Pathogenicity of mutations was determined using MutationTaster and PolyPhen databases. For p53, immunohistochemistry and sequencing were complimentarily used to assess the p53 status. Of 57 cases, 46 were considered prototypical ECCC by morphology and immunohistochemical profile (Napsin A-positive and ER-negative). Three cases were excluded because of insufficient sample for complete immunohistochemical analysis, and 6 had failed sequencing, resulting in 37 cases. Of the 37 remaining cases, 6/37 (16%) had predicted pathogenic mutations in the exonuclease domain of POLE with an allelic frequency >10%; however, no hot-spot mutations were identified. No cases were MMR-deficient. The gene most commonly affected was TP53 (59%, 22/37), followed by KRAS (13%, 2/15) and PIK3CA (13%, 2/15). The current study is the largest molecular analysis of pure ECCC reported to date. When strict classification criteria are applied, MMR-deficient and POLE mutated subtypes are not represented. Further consensus on what represents a deleterious POLE mutations is needed. The findings support separately studying histologically/immunohistochemically defined ECCC to identify characteristic molecular alterations in future studies.

Developmental abnormalities and malformations of the breast are rare and encompass a variety of genetic, syndromic, acquired and sporadic conditions. Abnormalities in development may include irregularities in the nipple areolar complex and/or the underlying glandular tissue, resulting in under or overdevelopment of breasts. Age of presentation and clinical severity is dependent on the underlying biologic cause. Abnormalities may involve the entirety of unilateral or bilateral breasts, particularly in association with syndromic conditions or endocrine abnormalities. Disordered development may also be focal, resulting in tumor-like lesions such as hamartomas, pseudoangiomatous stromal hyperplasia and gynecomastia. In this review, we discuss the disorders of breast development including etiologies, clinical presentations and corresponding histopathologic features., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Clear cell renal cell carcinomas (CCRCC) rarely metastasizes to the gynecologic tract. In this study, we analyzed a multi-institutional data set to provide insights into the clinical, morphologic, and immunophenotypic features of this phenomenon. Seventeen metastatic CCRCC involving the gynecologic tract [ovary/fallopian tube (n=9), vulva (n=2), uterine corpus (n=3), cervix (n=2), uterine serosa (n=1)] were analyzed. Mean patient age was 62 yr (range: 45-79 yr). Most cases (15/17) presented as a recurrence 6 to 72 mo postnephrectomy, 1 case was concurrently diagnosed, and 1 case (a cervical metastasis) was diagnosed prenephrectomy. In 10 cases, metastases to other locations were identified within 6 wk of the gynecologic tract lesion. The adnexa were the most common site of metastases and the mean tumor size of adnexal metastases was 3.7 cm; in only 2 of 9 cases were metastases bilateral and only 1 had external surface nodules. The morphologic and immunohistochemical features of metastatic CCRCC were compared with those of 102 müllerian clear cell carcinomas (müllerian CCC: 49 endometrial, 53 ovarian). Although CCRCC and müllerian CCC displayed extensive morphologic overlap, a higher mitotic index and a higher frequency of an alveolar pattern were seen in CCRCC, whereas diffuse hobnail cells, hyaline globules, tubulocystic pattern, or any papillary pattern were more frequently seen in müllerian CCC. CA-IX, CD10, and renal cell carcinoma antigen were more frequently expressed in CCRCC than müllerian CCC, whereas Napsin-A, CK7, and p504S showed the reverse. PAX8 and HNF1β did not significantly distinguish between the 2 groups. In summary, gynecologic tract metastases most often occur as a relapse of a previously resected CCRCC, and these relapses may occur many years postnephrectomy. Gynecologic tract metastases are often accompanied by concurrent metastases to other organs. The gross pathology of metastatic CCRCC in the ovary may potentially overlap with primary neoplasia. However, the expected morphology and immunophenotype of CCRCC are maintained in most gynecologic tract metastases. As such, although metastatic CCRCC and müllerian CCC may display significant overlap in pathologic features, several morphologic and immunophenotypic features are useful in their distinction.

Ninety years ago, at the Battle Creek conference, Papanicolaou introduced cervical exfoliative cytology. Since then, the "Pap test" has come a long way. The discovery of a causal relationship between cervical carcinoma and HPV infection opened the door for molecular testing and immunomarkers for HPV. The Clinical Laboratory Improvement Amendments, 1988, established quality assurance and quality control programs to monitor performance of cytology laboratories. The Bethesda System for reporting cervical cytology laid the foundations for cervical cytology education, implementation of management guidelines, and further research on cervical carcinogenesis. HPV vaccine penetration in both genders remains 62% or less., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Introduction: Treatment of advanced stage ovarian carcinoma is challenging, and despite surgical treatment and chemotherapy, the 5-year survival rate is estimated around 30%. Early recurrence and resistance to platinum-based chemotherapy are associated with poor prognosis and limited response to available second-line chemotherapy. The relative incidence of endocervical adenocarcinoma (EAC) compared with squamous cell carcinoma is increasing. Although the first-line treatment modality for early stage EAC is surgical resection, for locally advanced disease chemoradiation or neoadjuvant chemotherapy is used. Recently, folate along with its receptor alpha (FRA) has been studied as a potential target in gynecologic malignancy. The objective of this study was to elucidate FRA expression in chemotherapy resistant ovarian cancer and primary EAC., Methods: FRA expression was evaluated in tissue samples in an epithelial ovarian tumor microarray and 2 study groups: platinum resistant ovarian cancer and primary EAC. Staining intensity was analyzed with a semiquantitative staining algorithm., Results: FRA expression was positive in 32 of 40 (80%) ovarian tumors in the control group. In the platinum resistant ovarian cancer group, FRA was expressed in all 30 samples with moderate to strong staining. None of the EAC samples stained positive for FRA expression., Conclusions: FRA expression occurs frequently in epithelial ovarian cancer. Our data supports that FRA expressions are maintained after chemotherapy treatment. Folate targeted therapies may be most useful in patients with chemotherapy resistant disease based on high levels of FRA expression in these tumors. There is likely no benefit to folate therapy as an adjuvant treatment in EAC.

Background: Twenty-seven percent of neuroendocrine tumors (NETs) are associated with distant metastases, and in some patients, the primary site is unknown. Orthopedia homeobox protein (OTP) has been described as a useful marker for lung carcinoids (LCs) and for separating low-grade typical carcinoids (TCs) from intermediate-grade atypical carcinoids (ACs) in resection specimens. This study evaluated OTP, thyroid transcription factor 1 (TTF-1), and Ki-67 expression in fine-needle aspiration (FNA) samples of various NETs., Methods: A search for NETs diagnosed via FNA with subsequent resection was performed. Cell block sections were stained for OTP, TTF-1, and mindbomb E3 ubiquitin protein ligase 1 (Mib-1). Nuclear expression for OTP and TTF-1 was considered positive. Nuclear Ki-67 staining was reported as a percentage. Results were correlated with the grade and primary site for resection specimens., Results: Sixty-three FNA samples of NETs were identified: 14 liver samples, 14 pancreatic samples, 13 lymph node samples, 12 lung samples, 3 retroperitoneum samples, 2 small intestine samples, and 5 other samples. OTP was positive in 12 of 63 NETs (19%) from the following sites: lung (n = 8), liver (lung primary; n = 2), skin (n = 1), and lymph node (lung primary; n = 1). In well-differentiated NETs, only LCs were OTP-positive, whereas TTF-1 was positive in LCs and nonlung NETs (67% vs 7%). Within the LC category, OTP was positive in 100% of the TCs versus 17% of the ACs., Conclusions: OTP is specific for LCs because well-differentiated nonlung NETs are negative for OTP. OTP preferentially stains TCs over ACs. In well-differentiated NETs, OTP staining is highly specific for LCs, and in combination with a low Ki-67 index, it suggests a pulmonary TC. Cancer Cytopathol 2018;126:236-42. © 2018 American Cancer Society., (© 2018 American Cancer Society.)

Diagnosing malignancy in bile duct brushings is highly challenging. Seven reviewers of variable backgrounds and levels of participation in bile duct brushing sign out blindly reviewed 60 specimens (30 malignant with histologic confirmation and 30 benign (15 stented) with resection or ≥18 months of uneventful follow-up), testing the utility of 14 malignant characteristics. Eleven characteristics were statistically significantly associated with malignancy including 3-dimensional clusters (63% in malignant vs 3% in benign, odds ratio 50, P=0.0003), pleomorphism (62 vs 3, odds ratio 48, P=0.0004), 2-cell population (60% vs 3, odds ratio 44, P=0.0005), chromatin pattern (hypo/hyperchromasia) changes (70% vs 7%, odds ratio 33, P<0.0001), high nuclear-to-cytoplasmic ratio (48 vs 3%, odds ratio 27, P=0.0023), cytoplasmic vacuoles (43 vs 3%, odds ratio 22, P=0.0042), nuclear irregularity (70 vs 10%, odds ratio 21, P<0.0001), cellular discohesion (38 vs 3%, odds ratio 18, P=0.0082), hypercellularity (23% vs 0), nuclear molding (20% vs 0) and prominent nucleoli (21% vs 0). Necrosis and infiltrating inflammation were not helpful in identifying malignancy ('neutrophil cannibalism' was noted in 43% malignant); 21/30 (70%) malignant brushings had ≥3 malignant characteristics, while 23 (77%) benign brushings had none. Of 20 brushings with ≥4 characteristics, 1(5%) proved benign and showed detachment atypia, a close malignant mimicker in brushings. Identification of 3 characteristics maximized the combined sensitivity (70%), specificity (97%) and accuracy (83%), but sensitivity dropped as number of characteristics increased. Identification of 3/11 characteristics (3-dimensional clusters, pleomorphism, high nuclear-to-cytoplasmic ratio, nuclear irregularity, hypercellularity, discohesion, chromatin changes, vacuoles, prominent nucleoli, molding and 2-cell population) improves pathologists' overall performance greatly.

There have been several updates recently on the classification of uterine tumors. Endometrial carcinomas have traditionally been divided into 2 types, but some are difficult to classify and do not fit readily into either of the currently recognized categories. The Cancer Genome Atlas Research Network has recently defined 4 new categories of endometrial cancer on the basis of mutational spectra, copy number alteration, and microsatellite instability, which might provide independent prognostic information beyond established risk factors. The Society of Gynecologic Oncology, moreover, now recommends systematic screening of every patient with endometrial cancer for Lynch syndrome. The new definition of high-grade endometrial stromal sarcoma disregards the number of mitotic figures as a primary diagnostic criterion and instead specifies moderate atypia still resembling stromal origin but lacking the pleomorphism of undifferentiated uterine sarcoma; these tumors also harbor a JAZF1-SUZ12 gene rearrangement. Mitotic count, atypia, and coagulative necrosis are the main histologic criteria that define leiomyosarcoma. Determining the type of necrosis can be very challenging in patients receiving various treatment modalities for symptomatic fibroids before myomectomy, since key histologic features of ischemic-type necrosis are often absent. Ancillary stains including p16, p53, MIB-1, trichrome, and reticulin may be helpful in tumors harboring necrosis that is difficult to classify. Minimally invasive gynecologic surgeries have introduced histologic artifacts that complicate the diagnosis. It is essential to recognize these as procedure-related artifacts to avoid upstaging tumors and triggering unnecessary adjuvant treatment.

Introduction: Distinguishing primary ovarian clear cell carcinoma (CCC) from other tumors with clear cell features can be challenging. Hepatocyte nuclear factor-1β (HNF-1β) is a sensitive and specific marker for ovarian CCC. Immunohistochemical studies have shown HNF-1β positivity in a substantial proportion of clear cell renal cell carcinoma (RCC), hepatocellular carcinomas, and clear cell pancreatic adenocarcinoma. This study was designed to evaluate the role of HNF-1β in differentiating ovarian CCC from metastatic RCC and urothelial carcinoma (UC) with clear cell features., Materials and Methods: Formalin-fixed paraffin-embedded tissue microarrays of 103 clear cell RCC, 8 UC with clear cell features, and 15 ovarian CCC were studied using an HNF-1β antibody. Nuclear staining intensity and percentage of positively stained cells were assessed and scored from 0 to 3. Percentage of positive staining was scored based on the proportion of tumor cells stained., Results: Sixty-three of 103 (61.2%) of clear cell RCC were positive for HNF-1β. Staining intensity was weak in 32 of 103 cases (31.6%), moderate in 21 of 103 cases (20.4%), and strong in 10 to 103 cases (9.7%).Six of 8 (75%) UC with clear cell features showed positive staining predominantly in clear cell areas.All 15 cases of ovarian CCC were positive for HNF-1β., Discussion: Overall 61.2% of clear cell RCC and 75% of UC were immunopositive with HNF-1β in our study. HNF-1β has a limited utility in differentiating CCC of the genitourinary system from an ovarian primary.

Context: -High-molecular weight cytokeratins, such as cytokeratin 5 (CK5), are helpful to distinguish usual ductal hyperplasia (UDH) from atypical ductal hyperplasia (ADH) or low-grade ductal carcinoma in situ (DCIS). Few studies have looked at combining CK5 with estrogen receptor (ER) to differentiate UDH from ADH., Objective: -To evaluate the expression pattern of CK5 and ER as single or combined markers to separate UDH from ADH and low-grade DCIS., Design: -A total of 23 ADH, 10 low-grade DCIS, and 32 UDH whole-tissue slides were stained for ER, CK5, progesterone receptor (PR), and Bcl-2. Nuclear staining of ER and PR was scored as diffuse (>80%), focal (10%-80%), or negative (<10%). Cytoplasmic staining of CK5 and Bcl-2 was scored as diffuse (>60%), focal (10%-60%), or negative (<10%). Differences in staining patterns were evaluated., Results: -For ER staining: 94% of ADH/DCIS cases showed a diffuse staining pattern, whereas none of the 32 UDH cases showed diffuse staining. For CK5 staining: 96% of ADH/DCIS cases were negative or focally positive, whereas all 32 UDH cases had diffuse staining. The combination of ER and CK5 increased the sensitivity (94% to 97%). For PR staining: 11 of 23 ADH cases (48%), 6 of 10 DCIS cases (60%), and 4 of 32 UDH cases (13%) showed diffuse staining. Bcl-2 staining showed no statistical significance (P = .73)., Conclusions: -Although morphology remains the gold standard, ER and CK5 are useful makers to differentiate UDH from ADH. Progesterone receptor staining may have limited value, and Bcl-2 staining is not useful.

Uterine papillary serous carcinoma (UPSC) represents 10% of endometrial carcinomas. Significant number of patients initially present with extrauterine disease. The role of adjuvant treatment in low stage, especially polyp-confined UPSC is controversial. This multi-institutional study evaluated the significance of positive pelvic washing (PW) and adjuvant treatment on disease recurrence in a setting of endometrial polyp-confined UPSC. Surgical pathology files from 3 institutions were searched for cases of endometrial polyp-confined UPSC. Following histologic review, cases were clinically staged as Stage I, without myoinvasion or lymphovascular invasion. Clinicopathologic characteristics, results of PW, and type of adjuvant therapy were recorded. Statistical analysis using the Kaplan-Meier method for survival and Fisher exact test were performed. Thirty-three patients were included in the study. All patients were diagnosed with polyp-confined UPSC. The size of the polyp ranged from 0.3 to 4.3 cm. PW was positive for tumor cells in 8/33 (24%) patients. Twenty-two patients (66.6%) received some type of adjuvant treatment. Six patients (18%) developed recurrent disease. There was no significant difference in disease-free survival in the patients receiving adjuvant treatment versus not (P=0.375). However, there was significant association (P=0.0013) between positive PW and disease recurrence. Data are conflicting whether positive PW affects prognosis in low-stage endometrial carcinomas. Our study showed that in UPSC, malignant cells can be present in PW without lymphovascular invasion or myoinvasion and may have negative prognostic implication. Our data also reflect the controversies in the role of adjuvant treatment in endometrium-confined UPSC.

A 53-year-old woman underwent elective hysterectomy for symptomatic anemia secondary to abnormal uterine bleeding. She presented 15 months later with complaints of abdominal fullness. Abdominopelvic magnetic resonance imaging demonstrated multiple confluent enhancing solid masses centered in the pelvis and extending cranially to the level of the umbilicus. Additional separate nodules also were visible along the peritoneum. Biopsy demonstrated leiomyosarcoma. Additional clinical information was obtained, which revealed that the patient's prior hysterectomy was performed with morcellation. In November 2014, the United States Food and Drug Administration issued a warning discouraging the use of morcellation during hysterectomy and myomectomy because of the risk of seeding unsuspected malignancy. Radiologists should be aware of this potential complication of morcellation and its imaging appearance so that the correct diagnosis can be suggested in the imaging report.

Phenotypic differences between otherwise similar tumors arising from different gynecologic locations may be highly significant in understanding the underlying driver molecular events at each site and may potentially offer insights into differential responses to treatment. In this study, the authors sought to identify and quantify phenotypic differences between ovarian clear cell carcinoma (OCCC) and endometrial clear cell carcinoma (ECCC) using a proteomic approach. Tissue microarrays were constructed from tumor samples of 108 patients (54 ECCCs and 54 OCCCs). Formalin-fixed samples on microarray slides were analyzed by matrix-assisted laser desorption/ionization mass spectrometry, and 730 spectral peaks were generated from the combined data set. A linear mixed-effect model with random intercept was used to generate 93 (12.7%) peaks that were significantly different between OCCCs and ECCCs at the fold cutoffs of 1.5 and 0.667 and an adjusted P value cutoff of 1.0 × 10(-10). Liquid chromatography-tandem mass spectrometry was performed on selected cores from each group, and peptides identified therefrom were compared with lists of statistically significant peaks from the aforementioned linear mixed-effects model to find matches within 0.2 Da. A total of 53 candidate proteins were thus identified as being differentially expressed in OCCCs and ECCCs, 45 (85%) of which were expressed at higher levels in ECCCs than OCCCs. These proteins were functionally diverse and did not highlight a clearly dominant cellular theme or molecular pathway. Although ECCCs and OCCCs are very similar, some phenotypic differences are demonstrable. Additional studies of these differentially expressed proteins may ultimately clarify the significance of these differences., (Copyright © 2015. Published by Elsevier Inc.)

Magnetic resonance imaging is used to non-invasively stage and restage rectal adenocarcinomas. Accurate staging is important as the depth of tumor extension and the presence or absence of lymph node metastases determines if an individual will undergo preoperative neoadjuvant chemoradiation. Accurate description of tumor location is important for presurgical planning. The relationship of the tumor to the anal sphincter in addition to the depth of local invasion determines the surgical approach used for resection. High-resolution T2-weighted imaging is the primary sequence used for initial staging. The addition of diffusion-weighted imaging improves accuracy in the assessment of treatment response on restaging scans. Approximately 10%-30% of individuals will experience a complete pathologic response following chemoradiation with no residual viable tumor found in the resected specimen at histopathologic assessment. In some centers, individuals with no residual tumor visible on restaging MR who are thought to be at high operative risk are monitored with serial imaging and a "watch and wait" approach in lieu of resection. Normal rectal anatomy, MR technique utilized for staging and restaging scans, and TMN staging are reviewed. An overview of surgical techniques used for resection including newer, minimally invasive endoluminal techniques is included.

Objective: A malignant mixed müllerian tumor (MMMT) is a high-grade neoplasm commonly arising from the uterus. Patients present with bleeding and a mass protruding from the cervix. This study was designed to correlate Papanicolaou (Pap) smear findings with histological findings in women diagnosed with MMMT., Study Design: Women diagnosed with MMMT were identified. Preoperative Pap tests were correlated with histological findings. Statistical analysis was performed to assess associations between abnormal Pap tests and histological findings., Results: Forty patients with MMMT were included in the study. Age ranged from 37-85 years and tumor size ranged from 1.2 to 21 cm. In presurgical Pap tests (4 conventional and 36 liquid based), 11 smears (27.5%) were diagnosed as negative, 5 (12.5%) as atypical squamous cells of undetermined significance, 6 (15%) as atypical glandular cells, 16 (40%) as malignant and 2 (5%) as high-grade squamous intraepithelial lesion. Malignant cells detected on Pap smears showed a strong correlation with endocervical involvement by MMMT (p = 0.002). Larger tumors were more likely to involve the cervix (p = 0.0115)., Conclusions: The Pap test can predict cervical involvement by MMMT. On Pap smears, MMMT cells showed no correlation with other adverse histological features (lymphovascular invasion, myoinvasion or adnexal involvement)., (© 2015 S. Karger AG, Basel.)

The histotyping of high-grade endometrial carcinomas with clear cells may be subject to significant interobserver variability, which suggests that a biomarker that can distinguish endometrial clear cell carcinoma (CCC) from its mimics would be of diagnostic utility. This study assessed the usefulness of napsin A immunohistochemistry in the diagnosis of CCC, on the basis of an analysis of 77 cases diagnosed as such at 9 institutions. After being independently reviewed by a subset of 3 pathologists, cases for which there was diagnostic consensus among all 3 reviewers in agreement with the primary contributor (n=60) were used to establish a "consensus group" that served as a gold standard relative to which napsin A performance was assessed. Duplicate, 1.0-mm-core tissue microarrays were constructed from the 54 cases in the consensus group for which requisite materials were available, as well as from 49 endometrial endometrioid carcinomas (all grades) and 17 endometrial serous carcinomas. Napsin A immunohistochemical analysis was performed on the microarrays and on the 17 cases for which there was no diagnostic consensus, with scoring based on the proportion of immunoreactive cells (0, 1+, 2+, and 3+ indicative of 0, 1% to 25%, 26% to 49%, and ≥50% immunoreactive cells, respectively). The distribution of scores for the 49 CCC cases with evaluable cores was as follows: 0, n=6; 1+, n=6; 2+, n=8; 3+, n=29. Among the evaluable cases, the frequency of ≥1+ napsin A immunoreactivity was significantly higher in CCCs (43/49, 88%) than in endometrial serous carcinomas (1/13, 7.7%; P<0.0001) and endometrial endometrioid carcinomas (0/49, 0%; P<0.0001). The sensitivity, specificity, negative predictive value, and positive predictive value of ≥1+ napsin A expression in predicting the consensus clear cell histotype were 0.88 (95% confidence interval [CI], 0.75-0.95), 0.98 (95% CI, 0.9-1), 0.91 (95% CI, 0.86-0.96), and 0.98 (95% CI, 0.86-1), respectively. Napsin A expression was not associated with survival or clinicopathologic factors. In the group of cases without diagnostic consensus for CCC, 50% showed ≥1+ napsin A expression; all napsin A-negative cases had previously been classified as non-CCC by ≥2 reviewers, whereas only 37.5% of the napsin A-positive cases had been classified as CCC by 2 of the 3 reviewers. In conclusion, napsin A is a sensitive and specific biomarker of the clear cell histotype in endometrial carcinomas and accordingly may have diagnostic utility in their histotyping.

Objectives: To explore the diagnosis of hematolymphoid malignancies of the liver (hepatic lymphoma [HeL]) by image-guided fine-needle aspiration (FNA), which can often be difficult due to a low index of suspicion and nonspecific patient presentations, especially in the rare cases where the liver is the only site of disease (primary HeL [PHeL]). Understanding the clinical setting in which such lesions arise, as well as the cytomorphologic findings, may assist cytopathologists in making an accurate diagnosis and triaging samples for ancillary studies., Methods: In this retrospective study of 32 patients with HeL, the largest such study to our knowledge, we review the clinical and diagnostic features of HeL., Results: HeL and especially PHeL most commonly show a diffuse large B-cell lymphoma phenotype and have a poor prognosis (median survival of seven months). PHeL is strongly associated with human immunodeficiency virus infection (12/16 patients)., Conclusions: Image-guided FNA with immediate evaluation is a reliable means to obtain diagnostic material and triage for ancillary tests.

The expression of α-methylacyl-coenzyme-A racemase (AMACR) has previously been reported in 75% to 100% of urethral/bladder clear cell carcinomas, tumors that are known to display broad phenotypic overlap with their identically named müllerian counterparts. Herein, we assess the utility of AMACR in distinguishing endometrial clear cell carcinomas (CCCs) from endometrial serous carcinomas (ESCs) and endometrial endometrioid carcinomas (EECs). A total of 111 endometrial carcinomas in a tissue microarray, including 49 CCCs, 13 ESCs, and 49 EECs, were assessed for AMACR immunoreactivity, with results scored semiquantitatively (scores 0, 1+, 2+, 3+ for 0%, 1%-5%, 6%-50%, >50% immunoreactive cells, respectively). Fifty (45%) of the 111 carcinomas were AMACR positive, with the following score distribution: CCC: 0 (n = 12), 1+ (n = 12), 2+ (n = 3), 3+ (n = 22); EEC: 0 (n = 38), 1+ (n = 4), 2+ (n = 4), 3+ (n = 3); ESC: 0 (n = 11), 1+ (n = 1), 2+ (n = 0), 3+ (n = 1). AMACR expression was significantly more frequent in CCC (75%) than in ESC (15%) or EEC (22%); P < .0001. The sensitivity and specificity of AMACR expression in classifying a carcinoma as CCC were 0.75 (95% confidence interval [CI], 0.61-0.86) and 0.79 (95% CI, 0.66-0.88), respectively, with an odds ratio of 11.62 (95% CI, 5-28; P < .001) and an area under the curve of 0.79 (95% CI, 0.68-0.88). These findings indicate that AMACR expression is strongly associated with CCC and displays a relatively robust diagnostic test performance. However, its practical utility may be limited by the focal nature of its expression in 32% of the AMACR-positive CCC cases as well as its expression in 15% to 22% of the non-CCC histotypes., (© 2013.)

Evaluation of ER, PR and Her 2 are routinely performed on breast carcinomas. For accurate detection of these markers, compliance with the ASCO/CAP guidelines is recommended. Our previous study showed that alcohol fixation did not affect ER results when alcohol-fixed cell block (CB) sections were compared to formalin-fixed tissue sections, while PR and Her2 showed less concordance. The aim of this study was to evaluate and to compare ER, PR and Her2 IHC results on formalin-fixed CB sections to those observed on subsequent surgical (needle core or resection) specimens (SS). Fifty cases of formalin fixed CB samples obtained from primary (18%) and metastatic (82%) breast carcinomas were studied, all of which had subsequent SS available. ER, PR, and Her2 IHC studies were done on all samples and results were compared. ER results on formalin-fixed CB samples showed excellent correlation with SS (correlation coefficient cc = 0.82). While there was minimal improvement in PR results (cc = 0.433), Her2 detection did not improve by formalin fixation (cc = 0.439). Formalin fixation for CB preparations does not significantly improve the already good detection of ER positive breast tumors. The concordance rate in PR and IHC results between formalin-fixed CB and SS samples showed improvement as compared with the alcohol-fixed CB results. However, there was no improvement in detection of Her2 overexpression by using formalin fixation on cytology specimens., (Copyright © 2012 Wiley Periodicals, Inc.)

Fine-needle aspiration (FNA) is a screening and diagnostic tool used to triage the management of thyroid nodules. While FNA has proved to be a sensitive means of detecting common thyroid malignancies, less is known about the sensitivity and positive predictive value (PPV) of FNA for uncommon thyroid malignancies, including anaplastic thyroid carcinomas, medullary thyroid carcinomas, lymphomas, metastatic carcinomas, and other malignancies. We reviewed our experience with these uncommon malignancies sampled by thyroid FNA and recorded interpretations according to the Bethesda System. We compared the FNA interpretations to the follow-up cytology, histology, and flow cytometry. The sensitivity and PPV were as follows: anaplastic thyroid carcinoma (sensitivity 100%, PPV 89%), lymphoma (sensitivity 100%, PPV 100%), medullary thyroid carcinoma (sensitivity 83%, PPV 100%), metastatic carcinoma (sensitivity 80%, PPV 80%), and other malignancy (sensitivity 100%, PPV 100%). Four false-negative and two false-positive diagnoses were identified. While cases were nearly always triaged correctly, occasional pitfalls were encountered., (Copyright © 2011 Wiley-Liss, Inc.)

Fine-needle aspiration (FNA) is an important test for triaging patients with thyroid nodules. The 2007 National Cancer Institute Thyroid Fine-Needle Aspiration State-of-the-Science Conference helped instigate the recent publication of The Bethesda System for Reporting Thyroid Cytopathology. We reviewed 3,080 thyroid FNA samples and recorded interpretations according to the proposed standardized 6-tier nomenclature, and pursued follow-up cytology and histology. Of the 3,080 FNAs, 18.6% were nondiagnostic, 59.0% were benign, 3.4% were atypical follicular lesion of undetermined significance (AFLUS), 9.7% were "suspicious" for follicular neoplasm (SFN), 2.3% were suspicious for malignancy (SM), and 7.0% were malignant. Of 574 cases originally interpreted as nondiagnostic, 47.9% remained nondiagnostic. In 892 cases, there was follow-up histology. Rates of malignancy were as follows: nondiagnostic, 8.9%; benign, 1.1%; AFLUS, 17% (9/53); SFN, 25.4%; SM, 70% (39/56), and malignant, 98.1%. Thus, classification of thyroid FNA samples at the University of Virginia Health System, Charlottesville, according to The Bethesda System yields similar results for risk of malignancy as reported by others. Universal application of the new standardized nomenclature may improve interlaboratory agreement and lead to more consistent management approaches.

Depth of myometrial invasion by endometrioid adenocarcinoma (EMAC) is one of the most important predictive factors of disease recurrence. It is unclear whether myoinvasion arising in carcinomatous involvement of adenomyosis (AM) changes prognosis. The purpose of this study was to evaluate the significance and frequency of the tumor involved AM in otherwise low-stage cancers. Eighty-two hysterectomies with EMAC with less than 50% myoinvasion (T1a, FIGO IA), AM, and at least 2 years of follow-up information were reviewed. The tumors were divided into 4 histologic groups: group 1, no involvement of AM by EMAC (n=38); group 2, tumor involved AM surrounded by endometrial stroma (n=31); group 3, tumor involved AM with incomplete peripheral endometrial stroma (n=10); and group 4, tumor involved AM with invasion into adjacent smooth muscle (n=3). Tumor involved AM was in the inner half of the myometrium in 35 cases and in the outer half of the myometrium in 9 cases. The only adverse outcome was vaginal recurrence, which was noted in 2 of 82 patients; both the patients were from the control group. None of the patients with deep-seated tumor involved AM had tumor recurrence. In otherwise low-stage tumors, our data support the concept that tumor involvement of the deeply located AM does not affect prognosis. Myometrial-based foci of well-differentiated EMAC, completely or partially surrounded by endometrial stroma, most likely represents tumor colonized AM. Determining invasion out of these foci is subjective, and although limited by rarity in this study, carries no adverse outcome. Therefore, staging should be based on the myoinvasion noted at the native endomyometrial junction.

Background: Fine-needle aspiration (FNA) is a rapid and accurate procedure for the detection of breast carcinomas. The evaluation of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression by immunohistochemistry (IHC) is performed routinely on formalin-fixed, paraffin-embedded needle-core (NC) or excision tissue block (TB) preparations, according to the American Society of Clinical Oncology/College of American Pathologist guidelines. In this retrospective study, the authors compared expression levels of ER, PR, and HER2 in ethanol-fixed BC FNA cell block (CB) samples with expression levels in formalin-fixed NC and TB samples., Methods: Forty-one breast carcinoma CB samples with concurrent or subsequent NC and TB samples were identified. Patients who had received neoadjuvant or adjuvant chemotherapy were excluded. CB samples initially were fixed in 50% ethanol (4-12 hours), and this was followed by formalin fixation (minimum, 6 hours). NC samples were placed promptly in formalin for a minimum of 6 hours. Within 4 to 8 hours, TB samples were fixed in formalin for 6 to 48 hours. Fluorescence in situ hybridization (FISH) results were also compared., Results: IHC for ER on alcohol-fixed CB samples had good correlation with NC and TB samples. PR results on TB samples had excellent agreement with NC samples. A higher discordance rate wais observed when PR results were compared between CB samples and NC samples. HER2 detection on ethanol-fixed CB samples resulted in a higher rate of positive and equivocal staining than NC or TB samples. HER2 IHC on TB samples demonstrated better correlation with FISH results than CB or NC samples., Conclusions: Alcohol fixation did not affect ER results in breast carcinoma, but it may alter tumor cell PR antigenicity. The authors concluded that CB samples could be used to triage patients for tamoxifen therapy, but they are not reliable for the assessment of HER2 status; therefore, CB results should be correlated with results from NC or TB samples., (Copyright 2009 American Cancer Society)

Accurate assessment of estrogen receptor (ER), progesterone receptor (PR), and Her2 status of breast carcinomas is critical for predicting response to systemic therapies. Recently, developed rabbit monoclonal antibodies (RMab) are reported to have higher sensitivity than murine monoclonal antibodies (Mab). This study compares RMabs against FDA-approved Mab (FMab) in breast carcinoma cell block sections using visual and image quantification. Cell blocks from 52 breast cancers were studied. Immunohistochemistry using RMab (ER, PR, and Her2) was compared with FMabs (ER, PR, Dako) and HercepTest (HerFDA). Fluorescent in situ hybridization (FISH) was used as a reference standard for Her2. Slides were later scanned and reanalyzed with an automated cellular imaging system (ACIS III, Dako). Frequency of ER (38.5% vs. 36.5% for visual; 55.8% vs. 57.7% for image) and PR (28.8% vs. 36.5% for visual; 50% vs. 51.9% for image), and concordance (overall agreement is 71.2% and 75% for visual and image ER; and 84.6% and 59.6% for visual and image PR) were similar for both FMab and RMab, respectively. Overall agreement (53.8% vs. 77.1% for visual and image detection, respectively, using HerFDA and RMab) is poor to moderate for Her2. Visual Her2 (RMab) has the highest concordance (94.1%), and visual HerFDA has the lowest concordance (35.3%) with FISH. ER and PR analysis (FMab vs. RMab) are almost comparable using both detection methods with good overall agreement. For Her2 overexpression, RMab proved to be superior to HerFDA and showed excellent agreement with FISH results with both quantitative detection methods.

The female genital tract is rarely the primary site for hematologic malignancies; however, secondary involvement of this anatomic site is common. Primary lymphomas of the gynecologic tract are reported to represent less than 1% of extranodal non-Hodgkin lymphomas (NHL), and the majority of them being B-cell in origin. Diffuse large B-cell lymphoma is the most common subtype, whereas primary extraosseus plasmacytoma of the genital tract is rare.If clinically not suspected, these rare tumors pose a diagnostic challenge both for clinicians and pathologists. Clinical symptoms are often nonspecific and mimic other more common gynecologic malignancies such as squamous cell carcinoma of the cervix or endometrial adenocarcinoma. Although cervico-vaginal (Pap) smear is the primary screening method for cervical squamous cell carcinoma and its precursors, it is far less sensitive for detection of other primary or metastatic malignancies. In this review, we present three cases of hematologic gynecologic malignancies, two cases of primary NHL, and a case of acute myeloid leukemia with relapse as a pelvic mass, all of which were diagnosed on a liquid-based Pap test. In addition, we discuss the morphologic features of differential diagnostic entities of these rare tumors on conventional and liquid-based preparations., ((c) 2008 Wiley-Liss, Inc.)

Fine-needle aspiration (FNA) is a minimally invasive, fast, and accurate diagnostic method for the evaluation of patients with locally recurrent or distant metastases of malignant melanoma. In the vast majority of cases, the diagnosis is straightforward with the characteristic cytologic features well documented in the literature. Divergent differentiation (chondroid, neural, myofibroblastic, and osteocartilagenous) in a melanoma is rare and can potentially create diagnostic challenges if the evaluator is unaware of the same. We report a case of a 46-year-old female with a history of primary anal melanoma who presented with a groin mass. The FNA of the groin mass showed a neoplasm rich in chondroid matrix and raised the possibility of a second primary mesenchymal neoplasm rather than metastasis from the patient's known primary anal melanoma. A review of the histologic features of the anal melanoma showed divergent chondroid differentiation in the anal melanoma with the metastatic deposit in the groin exhibiting extensive chondroid differentiation. The differential diagnostic considerations are discussed., ((c) 2008 Wiley-Liss, Inc.)

Background: Immunohistochemistry is helpful in distinguishing metastatic carcinoma from atypical mesothelial cells; however, it is not useful in differentiating atypical mesothelial cells from malignant mesothelial cells. K homolog domain containing protein overexpressed in cancer (KOC), a member of the insulin-like growth factor mRNA-binding protein (IMP) family, also known as L523S and IMP3, is expressed during embryogenesis and in various malignancies. Using a mouse monoclonal antibody (L523S) against KOC, KOC expression was investigated in malignant tumors and reactive mesothelial cells in serous effusions., Methods: Seventy-six cases with paraffin-embedded pleural, pericardial, and peritoneal serous effusion cell blocks including 60 malignant serous effusions (11 malignant pleural mesotheliomas and 49 metastatic carcinomas) and benign pleural effusions (14 cases with reactive mesothelial cells and 2 cases with atypical cells with uncertain significance) were selected for immunohistochemical analysis with L523S, calretinin, and CK5/6., Results: Immunohistochemical studies showed that positive staining for KOC of variable degrees of intensity was observed in 47 of 60 cases in malignant serous effusions including 10 of 11 mesotheliomas and 36 of 49 metastatic carcinomas. The associated reactive mesothelial cells were negative for KOC but positive for calretinin and CK5/6. All 11 malignant mesotheliomas exhibited positivity for calretinin, and 9 of 11 cases had CK5/6 staining. In addition, 16 cases that were originally diagnosed either as pleural effusions with reactive mesothelial cells (14) or atypical cells with uncertain significance (2) were also tested for KOC expression. Interestingly, 3 of 16 cases exhibited various degrees of positivity for KOC, 2 of which were diagnosed as lung adenocarcinoma with a recurrence after tumor resection and 1 as malignant pleural mesothelioma., Conclusions: Anti-L523S antibody is a useful marker for the detection of malignant cells in serous effusions and it can have significant utility in differentiating reactive mesothelial cells from malignant mesothelioma and metastatic carcinoma in combination with calretinin and CK5/6 staining., ((c) 2007 American Cancer Society)