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Tumor-to-tumor metastasis is a well-recognized phenomenon. However, cerebellopontine angle tumor, especially vestibular schwannoma, is a rare location of metastasis, with only six cases being reported previously in English-language literature reviews. We report a case of a 57-year-old woman with underlying breast cancer (T2N3M1, stage IV) who presented with unilateral facial tics, paresthesia and hearing loss, who turned out to have vestibular schwannoma with adenocarcinoma metastasis., (Copyright © 2012. Published by Elsevier B.V.)

Objective: To report the case of a 78-year-old woman with mixed corticomedullary carcinoma of the adrenal gland, and to review other reported lesions that exhibit clinical and/or histopathologic features of both adrenal cortical and medullary differentiation., Methods: We describe the patient's clinical findings and laboratory test results, as well as the gross and histopathologic features of her tumor. We also review the literature pertaining to mixed corticomedullary adenomas and cortical tumors with clinical features of pheochromocytoma, and vice versa., Results: A 78-year-old woman with a 10-cm left adrenal mass was hospitalized for management of hypertensive urgency. Laboratory workup revealed elevated urinary metanephrine excretion and elevated serum dehydroepiandrosterone sulfate levels. She underwent left adrenalectomy. Pathologic examination of the lesion showed mixed cortical and medullary histologic characteristics, as well as gross and microscopic evidence of malignancy. Including the present case, we identified 17 cases of neoplasms that exhibit features of mixed corticomedullary differentiation., Conclusions: This report represents the first documented case of mixed corticomedullary carcinoma. Several benign lesions combine clinical, biochemical, and/or histopathologic evidence of both adrenal cortical and medullary differentiation, including mixed corticomedullary adenomas and corticotropin-secreting pheochromocytomas. The differential diagnosis of a lesion with mixed cortical and medullary features should also include a malignant neoplasm.

Metaplastic carcinoma of the breast, a rare neoplasm, usually presents at an advanced stage, metastasises to distant sites more frequently, has higher Ki-67 expression and is more often triple negative compared with other invasive breast cancers. Here, the authors discuss a case of an 84-year-old woman with triple negative mixed metaplastic breast carcinoma treated with radical modified mastectomy, axillary lymph node dissection and radiation therapy. Because of the rarity of the disease, the pathogenesis and the management remain controversial, thus contributing to overall poor prognosis.

Apocrine mixed tumor of the skin is a benign adnexal neoplasm usually posing no diagnostic problem for a histopathologist. The purpose of our investigation is to present a small series of 4 benign cutaneous apocrine mixed tumors of the skin that contained small foci of intravascular tumor deposits, a feature not previously described, to the best of our knowledge. The 4 lesions were identified retrospectively after a review of 312 apocrine mixed tumors and 51 eccrine mixed tumors in the collective files of the authors. In all cases, this feature was originally overlooked. The patients were 3 men and 1 woman, ranging in age at diagnosis from 29 to 66 years. Locations included nose (2), forehead (1), and the fifth toe (1). Histopathologically, all 4 neoplasms demonstrated typical features of a benign apocrine mixed tumor; 2 cases were classified as hyaline cell-rich tumors. In all cases, there were either blood or lymphatic vessels containing small intraluminal collections of neoplastic cells, which had the appearances of hyaline cells and immunohistochemically expressed cytokeratins and were partly immunoreactive for S-100 protein and calponin, thus indicating the myoepithelial phenotype. The intravascular location of the neoplastic cells was confirmed by CD31 staining. The nature of the vessels (lymphatics vs. blood vessels) was supported by staining for alpha smooth muscle actin, which stained pericytes in blood vessels. Lymphatic vessels were also stained for D2-40. No eccrine mixed tumor manifested intravascular tumor deposits. Follow-up of the patients revealed no recurrences or metastasis (range: 2-21 years). It is concluded that occurrence of intravascular involvement in benign apocrine mixed tumor of the skin is rare (approximately 1%-2%). This feature is discrete and is easy to overlook. At present, its significance is not completely clear. Until proved otherwise in future, we suggest to consider intravascular deposits in cutaneous apocrine mixed tumors as an innocuous phenomenon.

Gastric neuroendocrine neoplasms differ considerably in histology, clinicopathologic background, stage, and patient outcome, implying a wide spectrum of therapeutic options, hence the need for improved diagnostic and prognostic criteria to select appropriate therapy. Here, we tested the European NeuroEndocrine Tumor Society and the novel World Health Organization 2010 grade and stage classifications together with additional clinicopathologic and histologic parameters in a series of 209 gastric neuroendocrine neoplasms with a median follow-up of 89 months. Fifty-one grade 3 neuroendocrine carcinomas and 15 mixed endocrine-exocrine carcinomas of poor outcome were separated from 143 neuroendocrine tumors, including 132 G1 or G2 enterochromaffin-like (ECL) cell neoplasms and 11 G1 gastrin-cell, somatostatin-cell, or serotonin-cell tumors. Most G1 cases had excellent prognosis, even when metastatic, whereas G2 and G3 neoplasms had worse or very severe prognosis, respectively. The European NeuroEndocrine Tumor Society-World Health Organization 2010 proliferative grading system well correlated with patient survival. Structural histologic parameters were equally predictive and when combined with the European NeuroEndocrine Tumor Society-World Health Organization 2010 grading system in a "global grade" improved tumor prognostic stratification. The European NeuroEndocrine Tumor Society-World Health Organization 2010 staging system proved effective. Introduction of novel T (T(1a) and T(1b) or deep submucosal) and N categories (N(1), <3 nodes metastases; N(2), ≥3) allowed a simplified, equally informative 3-stage TNM system. Such improved diagnostic and prognostic criteria for gastric neuroendocrine neoplasms are proposed and discussed., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Aims:  Mammary metaplastic carcinoma is a rare breast carcinoma, and may present diagnostic difficulty. Alpha-B-crystallin has been recently reported to be expressed in basal-like and metaplastic carcinomas., Methods and Results:  Thirty-three metaplastic carcinomas, 44 conventional high-grade carcinomas and 28 mesenchymal spindle cell neoplasms as controls were assessed for their expression of αB-crystallin and conventional basal-like phenotypic markers CK5/6, CK14, p63, c-kit and epidermal growth factor receptor (EGFR) by immunohistochemistry. Alpha-B-crystallin staining was positive in 68% of the metaplastic carcinomas with cytoplasmic staining in all tumour cell components. CK5/6, CK14, p63, c-kit and EGFR stained 43%, 68%, 45%, 21% and 25% of the metaplastic carcinomas, respectively. Combining these markers, 84% of the metaplastic carcinomas expressed either αB-crystallin or CK14. In comparison, only 14% (six cases) of conventional high-grade carcinoma and 7% (two cases) of mesenchymal spindle cell neoplasm expressed αB-crystallin; all but one of these carcinomas were ER/PR/HER2 triple-negative., Conclusions: Using αB-crystallin for diagnosis of metaplastic carcinoma gives a 68% sensitivity, 88% specificity, 74% positive predictive value, 85% negative predictive value and 78% accuracy. The sensitivity is enhanced to 84% with combinations of αB-crystallin/CK14. Alpha-B-crystallin may be used as an adjunct marker in the diagnosis of metaplastic carcinoma., (© 2011 Blackwell Publishing Limited.)

Background/objective: Focal papillary thyroid carcinoma (PTC) arising within a follicular adenoma (PTCFA) represents a clinically significant, but rare, histopathologic subset of papillary carcinomas whose cytologic features have not been well described. This uncommon presentation of PTC may contribute to a subset of thyroid aspirates interpreted as 'atypia of undetermined significance/follicular lesion of undetermined significance' (AUS/FLUS)., Study Design: Seventeen fine-needle aspiration biopsy (FNAB) cases diagnosed as 'PTCFA' on corresponding surgical excision were identified from the archival records of 2 large academic medical centers. A control group of 40 FNAB comprised of 20 follicular adenomas (FA) and 20 PTC was identified (based on the corresponding surgical pathology diagnosis) for comparison. All 57 FNAB were reviewed in a masked fashion and scored for a series of 31 cytomorphologic features. The intraclass correlation between diagnostic categories and overall agreement between cytopathologists was statistically evaluated., Results: Aspirates of PTCFA were originally diagnosed as 'negative' (n = 3), 'AUS/FLUS' (n = 7), 'suspicious for a follicular neoplasm' (n = 3), 'suspicious for malignancy' (n = 3), and 'malignant' (n = 1). On masked review, the most common cytomorphologic features of PTCFA were a nonmacrofollicular cytoarchitectural pattern (71%), medium-large cell size (74%), and micronucleoli (79%). Intranuclear pseudoinclusions and a papillary architecture were absent in 85 and 88% of the cases, respectively. Relative to the 2 control groups, the PTCFA cases demonstrated overlapping features between FA and PTC for the majority of the 31 examined cytomorphologic features., Conclusion: PTCFA represent a rare subset of PTC that is difficult to recognize as PTC by FNAB. Most cases exhibit overlapping features between a benign thyroid nodule and conventional PTC, and they are often interpreted as 'AUS/FLUS'., (Copyright © 2011 S. Karger AG, Basel.)

Thymolipomas are rare tumours located in the anterior mediastinum. Sometimes these tumours may be combined with thymomas or lymphomas. We present a unique case of a thymic carcinoid arising within a thymolipoma. A 68-year-old patient presented with chronic chest and neck pain, which was initially thought to be caused by coronary artery disease. A chest x-ray, exercise tolerance test and coronary angiography were unremarkable. The following CT scan of the neck and chest showed a small tumour in the anterior mediastinum. A robotic-assisted thymectomy was performed and histological examination revealed a neuroendocrine tumour of the thymus within a thymolipoma. The patient was discharged 3 days after surgery in good general condition.

Oral myoepithelioma of soft tissue origin, an entity distinct from myoepithelioma of salivary glands, constitutes an extremely rare benign neoplasm, with only 1 previously published case, affecting the tongue of a 22-year-old woman. Ectomesenchymal chondromyxoid tumour (ECT) also is a very rare benign neoplasm of the oral cavity that has a strong predilection for the anterior dorsum of the tongue. The great similarities in the histologic and immunohistochemical characteristics of soft tissue myoepithelioma (STM) and ECT probably indicate that they refer to the same or closely related pathologic entities. The aim of this paper is to report a new case of STM affecting the dorsal tongue of a 45-year-old man. A review of the relevant literature is made and the relationship between oral STM and ECT discussed., (Copyright © 2010 Mosby, Inc. All rights reserved.)

Mixed epithelial and stromal tumor (MEST) of the kidney is a rare, typically benign lesion that occurs predominantly in perimenopausal women. At computed tomography (CT), it typically manifests as a multiloculated cystic renal mass with a variable proportion of solid and cystic components and containing internal septa that demonstrate heterogeneous and delayed contrast material enhancement. MEST may mimic a variety of benign and malignant renal lesions, such as adult cystic nephroma, complex renal cyst, and cystic renal cell carcinoma. The preoperative diagnosis of MEST can be problematic, and most cases are treated surgically. However, CT with two-dimensional multiplanar reformation and three-dimensional volume rendering helps define the diagnostic features of MEST and can assist in surgical planning., (© RSNA, 2010.)

Mixed epithelial and stromal tumors (MESTs) of the kidney are rare renal neoplasms characterized by mixed cystic and solid components. These tumors are typically present in middle-aged women as a flank mass, or as a cause of flank pain or hematuria. We outline the case of an older male who presented with an enlarging abdominal mass causing symptoms that suggested a partial small bowel obstruction. Management of the patient and a brief review are discussed.

Rosette-forming glioneuronal tumour (RGNT) of the fourth ventricle is a relatively new entity recently described. Neuronal and mixed neuronal-glial tumours have been incorporated in the same category in the WHO Classification of Nervous System Tumours. This category comprises heterogeneous neoplasms composed of neuronal and glial cells with various grades of differentiation. We present a case of papillary glioneuronal tumor occurring in a 44-year-old man with an unusual hemorrhagic onset. The clinical, morphological and immunohistochemical features are discussed and the published literature is reviewed.

Spermatic cord sarcomas (SCS) are very infrequent and sometimes misdiagnosed malignancies. Moreover, their optimal management remains undefined with ongoing controversy about the indications for adjuvant therapy. Histologically, liposarcomas are the most common type. Osteosarcoma is rarely observed in this location and combined tumours with this component have not been described. We present a case of SCS with mixed differentiation with both liposarcoma and osteosarcoma elements.

We report a 5 year-old boy with primary anaplastic pleomorphic xanthoastrocytoma (PXA) with whole neuroaxis dissemination at diagnosis who experienced the sudden onset of generalized convulsion. Head- and spinal magnetic resonance imaging (MRI) showed widespread gadolinium (Gd)-enhanced lesions extending to the bilateral frontal- and medial temporal lobes and the spinal cord. Subsequent MRI study demonstrated that the lesion size increased without any neurological deterioration. Under a histopathologic diagnosis of anaplastic PXA he underwent adjuvant chemotherapy consisting of 12 cycles of carboplatin and vincristine. The patient is alive without any neurological deficits; follow-up MRI showed that the lesions remained stable during 18 months of chemotherapy. We report a very rare pediatric case of primary anaplastic PXA with dissemination involving the entire neuroaxis at the time of diagnosis.

Study Objectives: To estimate the incidence of incidental miscellaneous uterine malignant neoplasms other than endometrioid adenocarcinoma detected during routine resectoscopic surgery in women with abnormal uterine bleeding (AUB) and to examine the effect of hysteroscopic surgery on long-term clinical outcome., Design: Prospective cohort study (Canadian Task Force classification II-3)., Setting: University-affiliated teaching hospital., Patients: Women with AUB., Intervention: From January 1, 1990, through December 31, 2008, one of the authors (G.A.V.) and several fellows performed primary hysteroscopic surgery at St. Joseph's Health Care in 3892 women with AUB. Of the 7 with malignant disease, one underwent hysteroscopic partial (n = 1) or complete (n = 6) rollerball electrocoagulation or endomyometrial resection. After diagnosis of uterine cancer, the women were counseled about the disease and management in accord with established clinical practice guidelines. Follow-up with office visits and telephone interviews ranged from 2 to 8 years (median, 6 years)., Measurements and Main Results: Of the 3892 women, 4 had undiagnosed and 3 had suspected miscellaneous uterine malignant neoplasms including 1 endometrial stromal sarcoma, 2 carcinosarcomas, 2 atypical polypoid adenomyomas of the endometrium, 1 minimal deviation adenocarcinoma of the cervix, and 1 smooth-muscle tumor of uncertain malignant potential. At 2 to 8 years of follow-up, 1 patient died accidentally after 1 year, 1 died of carcinomatosis of either coexisting breast cancer or a carcinosarcoma (postmortem examination was declined) after 1 year, and 5 were alive and well., Conclusion: Resectoscopic surgery in women with miscellaneous uterine malignant lesions not adversely affect 5-year survival and long-term prognosis.

Herein is described a unique case of breast carcinoma with two different types of giant cells noted in both cytological and histological specimens. A 51-year-old Japanese woman noticed a hard mass in the upper outer quadrant of her left breast. Aspiration cytology exhibited numerous anaplastic giant cells; the cytological diagnosis was high-grade ductal carcinoma, although a few osteoclastic giant cells were also observed. A left simple mastectomy and sentinel lymph node biopsy were performed. Histologically, approximately 90% of the tumor was composed of giant cells; conventional invasive ductal carcinoma and ductal carcinoma in situ were found focally at the periphery of the tumor. The main part of the tumor contained both anaplastic, neoplastic giant cells and non-neoplastic, osteoclastic giant cells that were distinguishable from nuclear atypism. The presence of the two types of giant cells was also confirmed on immunohistochemistry using a histiocytic marker (CD68) and two epithelial markers (AE1/AE3 and CAM5.2). Based on the latest World Health Organization classification, the diagnosis was pleomorphic carcinoma with osteoclastic giant cells. To the authors' knowledge there has been no previous report on this subject except for a single case mentioned in Rosen's Breast Pathology.

Papillary glioneuronal tumors are a newly recognized type of brain neoplasm characterized by prominent pseudopapillary structures and glioneuronal elements. All prior cases have shown that these tumors have an indolent course. The authors present 2 patients with an aggressive variant of the tumor. The first patient had dissemination of her tumor and the second had local spreading. Therefore, the authors conclude that papillary glioneuronal tumors do not always behave in a strictly benign fashion.

A 13-month-old Korean female presented with Cushing disease and diabetes insipidus. On MRI, a 3.5-cm, focally cystic, contrast-enhancing, sellar and suprasellar mass was noted. Aside from blood adrenocorticotropin (ACTH) and cortisol elevation, other pituitary hormone blood levels were normal or markedly reduced. The subtotally resected lesion consisted of synaptophysin-immunoreactive lobules of (a) large, polygonal, amphophilic, PAS-positive cells immunoreactive for ACTH, beta-endorphin, alpha melanocyte stimulating hormone (MSH), and keratin (CAM5.2) in some cells showing Crooke hyaline change, (b) less frequent acidophilic, growth hormone (GH) immunoreactive cells, and (c) rare luteinizing hormone (LH) and/or alpha subunit immunopositive cells. Also conspicuous were smaller cells resembling Rathke-type epithelium forming rosettes to sizable glands immunoreactive for EMA, keratin, S-100 protein, galectin-3 and rarely for synaptophysin and/or one of the above-noted adenohypophysial hormones. Transcription factors, including Neuro-D1 and Pit-1, were present in ACTH- and GH-producing cells, respectively, but only in occasional Rathke-type cells. The MIB-1 labeling index (LI) was 1.5% in secretory cells and 39% in Rathke-type epithelium. Ultrastructurally, the tissue resembled fetal pituitary of 10-12 weeks gestation and contained fully differentiated corticotrophs and somatotrophs, scant cells of glycoprotein-hormone producing type with small secretory granules, and glandular epithelial cells consistent with committed, but largely undifferentiated Rathke-type epithelium. We consider the tumor as a pituitary blastoma, a lesion composed of multiple cell types common to the development of the affected organ based upon (a) prominence of primitive Rathke-type epithelium, (b) disposition of secretory cells in lobules rather than acini, (c) the limited range of secretory cells represented, (d) the presence of their corresponding transcription factors, and (e) ultrastructural features indicating orderly development of the 10- to 12-week embryonic stage.

An unusual tumor of the neck in a 56-year-old female is reported. The tumor was composed of tubules and small cords of epithelial cells dispersed in the fibromyxoid and adipose stroma. At the periphery, the tumor was not encapsulated and its border was intermingled with the subcutaneous fat. Lack of decapitation secretion and the absence of long tubules suggested an eccrine origin; however, in some of the tumor areas, the cells showed brightly eosinophilic copious cytoplasm that may indicate an apocrine differentiation. As an area of chondroid metaplasia was identified, the diagnosis of a mixed tumor was rendered. This unusual type of skin adnexal neoplasm with unique relation of the epithelial component to the surrounding adipose tissue requires differentiation with the primary cutaneous and metastatic carcinomas.

Purpose: To establish an MR factor analysis technique for two-dimensional (2D) MR dynamic structures of benign and malignant salivary gland tumors., Materials and Methods: Dynamic contrast-enhanced MRI using a surface coil was performed on 36 patients with benign (N = 24) or malignant (N = 12) salivary gland tumors. Signal intensity kinetics in each pixel of the tumors after contrast medium injections were semiautomatically categorized into four patterns (slow uptake, rapid uptake with high washout, rapid uptake with low washout, and flat). The 2D distributions of the kinetic patterns in the tumors were compared with the histological features of the corresponding parts of the excised tumors and with overall kinetics obtained by a conventional analysis., Results: The MR factor analysis technique allowed the pixel-to-pixel evaluation of the contrast enhancement kinetics of the salivary gland tumors. The 2D distributions of the time-intensity curve (TIC) patterns correlated well with the histological features of the salivary gland tumors and allowed more detailed dynamic structures of the tumors compared with the results obtained by the conventional dynamic study analysis., Conclusion: The proposed MR factor analysis would be clinically feasible to diagnose salivary gland tumors and tumor-like lesions., (2008 Wiley-Liss, Inc)

Although first intimated in the 1970s, mixed epithelial stromal tumor has been recognized as a diagnostic entity for less than 10 years, with an identity that has been challenged by overlap between other cystic renal neoplasms, most notably with cystic nephroma. We report the first case of a bilateral mixed epithelial stromal tumor occurring in a 41-year-old dialysis-dependent woman, notably also the first case reported in a patient with end-stage renal disease. The neoplasms occurred 5 years apart and were diagnosed as mixed epithelial stromal tumor in both instances. We describe the presentation and pertinent radiologic, histologic, and immunophenotypic findings of these neoplasms with a review of the current debate regarding mixed epithelial stromal tumor and cystic nephroma taxonomy.

This article reviews the ultrasound, computed tomography, and magnetic resonance imaging features of rare solid tumors of the pancreas with attention to distinctive imaging appearances, which can help radiologists to discriminate between the different entities. Various uncommon solid pancreatic neoplasms, including exocrine and endocrine epithelial tumors, mesenchymal tumors, and metastases, are reviewed, with emphasis on key differential points, including morphologic features and patterns of contrast enhancement.

We report 10 cases of a morphologically distinct vaginal polyp which has hitherto not been characterized. The polyps occurred in women aged 39 to 78 years (most were postmenopausal) and were from 1.0 to 3.0 cm. Most of whose location is known to us were in the upper vagina. Histologically, all the polyps were remarkably similar and composed of well-circumscribed expansile nests of epithelial cells embedded in a hypocellular fibrous stroma. The epithelial elements, which were morphologically bland, were predominantly glycogenated or nonglycogenated squamous in type but small tubules were present at the periphery of some of the nests in all cases. Some of the squamous nests exhibited central necrosis with or without calcification and, in 3 cases, some contained keratin pearls. In 3 cases, a few tubules unassociated with squamous elements were present. In 3 of 4 cases tested, the cells lining the tubules were positive with prostatic acid phosphatase and in 2 of 4 with prostate-specific antigen. The epithelial elements reacted with broad-spectrum cytokeratins and cytokeratin 7 but the mesenchymal component was negative. The squamous elements were estrogen receptor positive and the mesenchymal component estrogen and progesterone receptor positive. The histologic features of this polyp, which we term "tubulo-squamous polyp of the vagina," are constant and distinctive and differ from other polyps and from mixed tumor of the vagina. Several cases reported in the literature as vaginal mixed tumor or Brenner tumor are likely examples of this entity. Possible theories of histogenesis include a Mullerian origin, derivation from mesonephric remnants or derivation from urogenital sinus-derived epithelium. Positive staining in some cases with prostatic acid phosphatase and prostate-specific antigen raises the possibility of ectopic prostatic tissue, although the overall appearance is different from that entity, or derivation from paraurethral Skene glands, the female equivalent of prostatic glands in the male.

We present a 3-year-old child with Cushing's syndrome due to an ACTH-secreting metastatic pancreatoblastoma. This malignancy is a rare cause of Cushing's syndrome, particularly at pediatric age. We describe her course including the use of ketoconazole to alleviate hypercortisolemia.

A 51-year-old, perimenopausal, female patient with 1-month history of right flank pain who was diagnosed with a renal mass and underwent nephron-sparing partial nephrectomy is presented. The renal mass was found to be a benign, biphasic tumor composed of an epithelial component, consisting of ducts of variable size scattered within a mesenchymal component, composed of spindle cells arranged in sheets and fascicles. No atypia, mitosis, or necrosis was found. The spindle component shows desmin, smooth muscle actin, and estrogen and progesterone receptor positivity immunohistochemically. The diagnosis of benign mixed epithelial and stromal tumor of the kidney is rendered. No recurrent disease has been detected during 2 years of follow up.

This article describes the historical development of pediatric pulmonary metastasectomy but demonstrates that progress has been slow in understanding its proper applications. Because many pediatric metastatic tumors are rare, surgeons have grouped together patients of different histologies for the generation and analysis of case series. By examining tumor types individually, however, it is seen that certain histologies (adrenocortical carcinoma, alveolar soft part sarcoma, osteosarcoma) mandate surgical metastasectomy for patient survival. Other pediatric tumors (Wilms tumor, Ewing's sarcoma) are radiation sensitive, and the application of metastasectomy is controversial. In the case of still other types of tumor (neuroblastoma, differentiated thyroid cancer, rhabdomyosarcoma), metastasectomy is seldom performed except in highly unusual situations. Techniques for minimally invasive biopsy and for muscle-sparing thoracotomy are described for pediatric patients.

The recently described mixed epithelial and stromal tumor (MEST) of the kidney and adult cystic nephroma (CN) (multilocular cyst) are rare benign cystic renal neoplasms that are composed of epithelial and stromal elements. Consensus criteria for distinguishing these entities have not been well established. Our objective in this study was to evaluate cases of CN and MEST to define the morphological, immunophenotypic, and clinical features of these two entities. Eleven cases from the files of a single institution diagnosed from 1996 to the present as either CN or MEST were reviewed. Architecturally, all lesions were composed of multiple noncommunicating cysts lined by a single layer of epithelial cells. All cases had areas with increased stromal cellularity and 8 cases had ovarian-like stroma present at least focally within the tumor. No stromal or epithelial cell atypia, blastemal elements, or increased mitotic activity was appreciated. The immunoprofile was also similar in the 7 cases stained and included epithelial reactivity with keratin and CAM 5.2 and stromal reactivity with estrogen receptor, progesterone receptor, smooth muscle actin, WT-1, vimentin, and focal desmin. All cases have acted in a benign fashion with no history of recurrence or metastasis. We propose that CN and MEST of the kidney represent a spectrum of the same entity. If the diagnosis of CN is limited to cases that are comprised entirely of thin fibrous-walled cysts, all 11 of our cases would be classified as MEST.

Three cases of mixed epithelial and stromal tumor of the kidney with their imaging findings are described; these cases have not been reported previously in the radiology literature. This benign tumor contains epithelial and spindle cell stromal components and arises exclusively in adult women. It is characterized morphologically by a solid and cystic nature with delayed enhancement.

Context: Mixed epithelial-stromal tumor of the kidney is a recently recognized benign renal tumor that usually occurs in adult women and typically forms a sizable lesion with solid and cystic areas. The recognized morphologic spectrum of this recently described entity is evolving., Objective: To review the clinicopathologic features of 3 small mixed epithelial-stromal tumors of the kidney that were incidental findings in kidneys removed for other reasons., Design: The clinical presentation and morphologic findings of the 3 cases were reviewed. A panel of immunohistochemical stains was performed., Setting: Academic medical center., Results: All 3 lesions contained predominantly fascicles of smooth muscle mimicking leiomyoma, but they also had cellular subpopulations of smaller, müllerian-appearing stromal cells. Tubules present within the lesion were most abundant at the periphery, suggesting that they might be entrapped. Although only the spindled smooth muscle cells were immunoreactive for muscle markers desmin and actin, both the spindled smooth muscle cells and the cellular müllerian-appearing stromal cells demonstrated diffuse nuclear labeling for estrogen and progesterone receptors., Conclusions: Mixed epithelial-stromal tumor of the kidney may present as an incidental stromal-predominant lesion within the kidney. Such lesions are easily confused with leiomyomas or stromal-predominant angiomyolipomas.

A mixed epithelial and mesenchymal tumor of the liver arising in an adult is rare and is mostly classified as sarcomatoid hepatocellular carcinoma (HCC). In this study, a case of sarcomatoid HCC in an adult with hepatoblastoma (HB)-like features, which produced difficulty in the differential diagnosis between sarcomatoid HCC and mixed HB, is presented. The epithelial component of the tumor composed of poorly differentiated HCC, Edmondson's grade III, and more primitive components, which were embryonal and small cell undifferentiated components of HB-like areas. The small undifferentiated cells surrounded HCC and the embryonal component of HB-like area, and revealed transition partly to areas of rhabdomyosarcoma. A small portion of chondrosarcoma was also noted. Immunohistochemical analysis showed that HCC and the embryonal component of HB-like areas expressed alpha-fetoprotein (AFP) and cytokeratin 8. The small undifferentiated cells were negative for AFP but stained with cytokeratin 8 as well as CD56, which is a marker of primitive cells in many sarcoma and HB. It is not certain whether small undifferentiated cells belong to hepatic progenitor cells or primitive mesenchymal cells. Polymerase chain reaction-single-strand conformation polymorphism analysis for beta-catenin mutation using microdissection revealed no mutation of any components. A review was undertaken of the cases previously reported as adult hepatoblastoma without detailed immunohistochemical study and consider many of them may be sarcomatoid HCC. These primitive and sarcomatoid components would be arising from the dedifferentiation process of HCC.

We report the case of a corticomedullary mixed tumor of the adrenal gland in a 55-year-old woman with a left adrenal mass who presented with mild symptoms of Cushing syndrome and an elevated urinary cortisol level. The patient underwent a left adrenalectomy. A well-circumscribed 2.5-cm mass, composed of an admixture of adrenal cortical cells and pheochromocytes, and an incidental 0.7-cm myelolipoma were present in the resected left adrenal gland. The diagnosis of adrenal corticomedullary mixed tumor was confirmed by both immunohistochemistry and electron microscopy. To our knowledge, this is the eighth well-documented report of this rare tumor.

Glioneuronal neoplasms of the CNS comprises a heterogeneous group of generally low-grade tumors expressing glial and neuronal cells of varying differentiation. Recently, a new variant of the glioneuronal tumors has been identified. We present a case of a glioneuronal tumor located in the left frontal lobe of a 16-year-old boy who developed seizures 6 months after brain concussion. MR scan demonstrated an irregular, but well circumscribed, mixed cystic and solid tumor with contrast enhancement in the solid part. Histology showed a papillary glioneuronal tumor. The tumor is indolent with no sign of recurrence after gross total resection.

The co-existence of schwannoma and meningioma as a mixed intracranial tumour is uncommon and so far only eight cases have been published in the literature. Because of rarity, we report a unique case of mixed tumour having schwann cell and meningeal components, in a patient with neurofibromatosis type -2 (NF-2). The possible mechanisms for the occurrence of these mixed tumours are discussed.

Corticomedullary mixed tumors of the adrenal gland are quite rare, with only five well-documented cases reported in the literature.(1-4) Herein, we report the light microscopic and immunohistochemical features of two cases of this rare tumor. Patient 1 is a 34-year-old woman who presented with hypertension, hair loss, and amenorrhea of 1-year duration. Patient 2 is a 52-year-old woman who presented with flank pain and what appeared to be a renal mass on arteriogram with no history of hypertension, Cushing's syndrome, or other endocrine abnormalities. At surgery, the tumor was noted to arise from the adrenal gland rather than the kidney and adrenalectomy was performed. In both cases, the surgically resected specimens consisted of a well-circumscribed, single adrenal mass surrounded by a rim of uninvolved adrenal cortical tissue. The tumors were composed of adrenal cortical cells intimately admixed with pheochromocytes. Immunohistochemical studies highlighted these two cellular components. The pheochromocytes were strongly reactive with chromogranin and the sustentacular cells with S-100 protein, whereas the adrenal cortical cells reacted specifically with inhibin. Thus, we report two additional cases of mixed corticomedullary tumor of the adrenal gland. Ann Diagn Pathol 5:304-308, 2001. This is a US government work. There are no restrictions on its use.

In the skin, endocrine tumors showing areas with nonendocrine features and nonendocrine tumors showing endocrine differentiation are present. (1) Neuroendocrine carcinomas with nonendocrine differentiation: Merkel cell carcinoma (MCC) of the skin has been frequently described in association with squamous cells carcinoma (SCC) which can arise separately (as synchronous or metachronous lesions) from MCC as well as closely intermixed. In the first event the possibility that the lesions are sustained by same causative factors (among which sun exposure is the most probable) is suggested. In cases of lesions closely intermixed the possibility of an origin from a common precursor is suggested. Furthermore, cases of MCC have been described to contain glandular, melanocytic, striated muscle, and lymphoepithelioma-like features. These latter findings further support the hypothesis of tumors showing divergent differentiations. (2) Nonendocrine tumors showing endocrine differentiation: Basal cell carcinoma (BCC) was the first cutaneous nonendocrine tumor described to contain neuroendocrine granules. Presence of endocrine features were subsequently confirmed with immunohistochemical studies. Endocrine features were then described in sweat gland apocrine and eccrine carcinomas. Endocrine elements present in BCC and in sweat gland carcinomas do not show morphological and immunohistochemical features of Merkel cells. Thus the possibility that these tumors develop an immature Merkel cell or a new type of endocrine cell of the skin is suggested. Tumors with follicular differentiation such as trichoblastomas and trichofolliculomas contain a high number of Merkel cells. As Merkel cells are numerous in hair follicles of human fetal skin, the possibility that these tumors recapitulate the human skin embryogenesis is suggested.

A rich variety of neuroendocrine cells are present in the normal prostate gland. Prostatic carcinoma may show divergent differentiation towards a neuroendocrine phenotype in the form of neuroendocrine small cell carcinoma or carcinoid-like tumors. Much more common is focal neuroendocrine differentiation in prostatic adenocarcinoma which may be pronounced in approximately 10% of adenocarcinomas. The prognostic significance of focal neuroendocrine differentiation in prostatic carcinoma is controversial but current evidence suggests an influence on prognosis related to hormone resistant tumors and/or a role in the conversion to a hormonal resistant phenotype. Chromogranin A appears to be the best overall tissue and serum marker of neuroendocrine differentiation. Chromogranin A serum levels may be useful in the assessment of the emergence of and/or progression of hormone resistant cancer.

We report a case of asymptomatic mesoblastic nephroma in a 54-year-old woman. The tumor showed immunohistochemical reactions similar to developing nephrons. Electron microscopy showed immature tubules with numerous intracytoplasmic intermediate filaments. Recent studies support the concept of pathogenesis of the mesoblastic nephroma originating from collecting ducts. However, this case exhibited a complex pattern of antigenic expression not restricted to the collecting ducts, but including the glycoprotein CD24 and the neural cell adhesion molecule (NCAM). The following differential diagnoses will be discussed: benign mixed epithelial and stromal tumor, metanephric adenoma, and nephrogenic adenofibroma.

Surgery plays an important part in the overall management of primary central nervous system (CNS) germ cell tumors. While the general surgical objectives in patients with these neoplasms are similar to those with other types of CNS tumors, to obtain an accurate histopathologic diagnosis and to contribute towards improving patient survival the unique features of germ cell tumors have necessitated novel treatment strategies. Pure germinomas are exquisitely radiosensitive, and prior studies have shown no survival benefit from radical resection of such lesions. However, a significant proportion of CNS GCTs contain admixtures of nongerminomatous GCT (NGGCT) elements and are less responsive to aggressive chemotherapy and irradiation. Biopsy of these malignant GCTs carries the risk of histologic sampling error. Nevertheless, a proportion of NGGCTs produce tumor markers detectable in serum or CSF and may be accurately diagnosed without surgical intervention. Although the role of radical surgical resection has not been definitively demonstrated in the literature, recent data from an international cooperative trial suggest a survival benefit from radical resection of localized NGGCTs. Lastly, increasing experience has supported the role of delayed resective ("second-look") surgery for patients with negative tumor markers but residual radiographic abnormalities after initial chemotherapy. Resection of such lesions has typically yielded necrosis or teratoma, which may be cured by surgical resection, and obviated the need for additional chemotherapy or irradiation.

The term amphicrine refers to cells, and tumors, which show both exocrine and endocrine features. Author s aim was to analyse the characteristics of these neoplasms. 40 suspicious cases were reviewed. Mucin-stains (PAS, diastase-PAS, Stains-all, Alcian-blue), immunohistochemistry (antibodies against Neuron-Specific Enolase (NSE), and Chromogranin A (CGA), and electronmicroscopic studies were performed to demonstrate exocrine and/or endocrine features of the tumor cells. By means of these methods, 16 cases turned out to be amphicrine tumors. Among them, there were 4 sinonasal, 1 bronchial, 1 mediastinal, 8 gastrointestinal and 2 suprarenal gland neoplasms. In connection to the subject, a brief review is given of amphicrine tumor, regarding its etiological and pathological aspects. These tumors form a distinct clinicopathological entity and should be separated from both neuroendocrine tumors and adenocarcinomas.