Melanotic paraganglioma of the uterus

Cervical Small Cell Variant of Paraganglioma With Sarcomatous Transformation: Report of a Unique Case

We report a unique primary cervical neoplasm in a 44-yr-old woman which we believe, based on the morphology and immunophenotype, represents an extremely unusual small cell variant of paraganglioma. This represents the first report of a primary cervical paraganglioma. Following chemoradiation treatment, the tumor underwent malignant transformation into an S100 and SOX10 positive sarcoma, morphologically and immunohistochemically resembling a malignant peripheral nerve sheath tumor, which we believe represents a sarcoma derived from the sustentacular cells of the paraganglioma. Mutational analysis detected a nonsense mutation of NF1 gene in the sarcoma. This further supports the diagnosis as both somatic and germline NF1 mutations have been associated with paragangliomas and malignant peripheral nerve sheath tumors. Targeted RNA sequencing (ARCHER, expanded sarcoma panel) covering many known genes implicated in sarcoma development, did not reveal any other molecular alteration (fusion or internal tandem duplication).

Differential diagnosis and unusual diffuse cytokeratin expression in renal paraganglioma: A case report

Paraganglioma is a rare neuroendocrine tumor arising from undifferentiated cells of the primitive neural crest. We report a case of renal paraganglioma in a 67-year-old patient. Computed tomography demonstrated a solid mass in the middle and lower pole of the right kidney. Sonography revealed an enlarged right kidney with an irregular shape but distinct border. Renal cell carcinoma was diagnosed provisionally; the tumor was completely resected and submitted for pathological examination. Unexpectedly, histopathology and immunohistochemistry confirmed paraganglioma arising from the renal parenchyma. In this study, we report the exceptional occurrence of Paired box gene 8 (PAX-8) expression in a renal paraganglioma. In addition, we demonstrated diffuse cytokeratin positivity in this renal paraganglioma. Although our report of a paraganglioma originating from the kidney is not unique, our finding expands the known immunophenotypic spectrum of this tumor. The awareness of the possible occurrence of cytokeratin diffuse positivity in paraganglioma is relevant to avoiding misdiagnosis of paraganglioma.

Primary Melanotic Paraganglioma of Thyroid Gland: Report of a Rare Case With Clinicopathologic and Immunohistochemical Analysis and a Literature Review

Background:

Pigmented paraganglioma is a special type of paraganglioma, and it is rare in the thyroid.

Case Presentation:

We report a case of a 41-year-old woman who had complained of a mass in the thyroid gland. Histology revealed tumor cells arranged in a nest-like or organoid pattern, separated by delicate fibrovascular septa. Two distinct components were observed. In the first, which constituted the majority of the tumor cells, no pigments were observed. In the second, a few cells with pigment showed intercellular substance, but the structure was unclear. Using immunohistochemistry, cells in the first component were confirmed to be diffuse strong positive for synaptophysin, but negative for chromogranin A, pan-cytokeratin, calcitonin, and thyroglobulin. About 1% of tumor cells were stained by Ki-67. In the margins of the tumor, a few cells were observed to be positive for HMB-45 and Melan A after bleaching by oxalic acid. The stromal cells were positive for S-100. Using electron microscopy, a few cells containing many round melanin bodies with greater electron density granules of nonuniform size were observed. The diagnosis of primary melanotic paraganglioma of the thyroid gland was made.

Conclusion:

Primary melanotic paraganglioma of the thyroid gland is a rare, low malignant potential tumor. To the best of our knowledge, this is the first case described.

Primary Pigmented Neuroectodermal Tumor of the Uterine Cervix

A primary pigmented neuroectodermal tumor of the uterine cervix is described. The patient was 57 years old when she presented with vaginal bleeding. She underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy and pelvic lymph adenectomy, followed by chemotherapy. Histologically, the tumor was characterized by the concomitant presence of two neural crest derivatives, neuroblasts and melano cytes. The latter cells were arranged in a tubulopapillary fashion and contained abun dant melanin. Histochemical, immunohistochemical, and electron microscopic exami nation confirmed the diagnosis. The patient was alive without evidence of disease 5 years later. An origin of this tumor from abnormally migrated neural crest cells is suggested. Int J Surg Pathol 2(1):31-36, 1994

Somatic RET mutation in a patient with pigmented adrenal pheochromocytoma

Pheochromocytomas (PCC) and paraganglioma (PGL) are rare neuroendocrine tumors arising from chromaffin cells of the neural crest. Mutations in the RET-proto-oncogene are associated with sporadic pheochromocytoma, familial or sporadic medullary thyroid carcinoma (MTC) and multiple endocrine neoplasia type 2. In the past, only few cases of pigmented PCCs, PGLs, and one case of pigmented MTC have been reported in the literature. Herein, we present the case of a 77-year old woman with a history of Tako-tsubo-cardiomyopathy and laboratory, as well as radiological, high suspicion of pheochromocytoma, who underwent left-sided adrenalectomy. The 3 cm tumor, which was located on the upper pole of the left adrenal, appeared highly pigmented with dark red to black color. Histologic examinations revealed highly pleomorphic cells with bizarre, huge hyperchromatic nuclei, that immunohistochemically were positive for chromogranin A and synaptophysin, focally positive for HMB45 and negative for melan A. These clinical and pathological features led to the diagnosis of the rare variant of a melanotic 'black' pheochromocytoma. In our case a somatic RET mutation in exon 16 (RET c.2753T>C, p.Met918Thy) was detected by targeted next generation sequencing. In summary, this case represents a rare variant of catecholamine-producing tumor with distinct histological features. A potential relationship between the phenotype, the cellular origin and the genetic alterations is discussed.

LEARNING POINTS

Pheochromocytoma is a rare neuroendocrine tumor.Pigmentation is seen in several types of tumors arising from the neural crest. The macroscopic black aspect can mislead to the diagnosis of a metastasis deriving from a malignant melanoma.RET mutation are seen in catecholamine and non-catecholamine producing tumors of the same cellular origin.

A rare case of extra-adrenal pheochromocytoma localized to the ovary and detected via abdominal computed tomography angiography

Extra-adrenal pheochromocytomas are rare tumors that originate from the chromaffin tissue of the sympathetic nervous system. Ovarian extra-adrenal pheochromocytoma is even more rare. The present study reports a rare case of an extra-adrenal pheochromocytoma that was localized to the right ovary, but was gynecologically asymptomatic. Computed tomography angiography (CTA) detected the tumor and indicated that it was well defined, highly vascularized and obtained its blood supply from the right ovarian artery. This is the second case of ovarian extra-adrenal pheochromocytoma reported in the literature, and the first description of the CTA manifestations in the ovary. Gynecologists and radiologists should consider the possibility that an ovarian mass could be an extra-adrenal pheochromocytoma, which would allow time to prepare appropriately for the surgical removal of the mass.

Paragangliomas: update on differential diagnostic considerations, composite tumors, and recent genetic developments

Recent developments in molecular genetics have expanded the spectrum of disorders associated with pheochromocytomas (PCCs) and extra-adrenal paragangliomas (PGLs) and have increased the roles of pathologists in helping to guide patient care. At least 30% of these tumors are now known to be hereditary, and germline mutations of at least 10 genes are known to cause the tumors to develop. Genotype-phenotype correlations have been identified, including differences in tumor distribution, catecholamine production, and risk of metastasis, and types of tumors not previously associated with PCC/PGL are now considered in the spectrum of hereditary disease. Important new findings are that mutations of succinate dehydrogenase genes SDHA, SDHB, SDHC, SDHD, and SDHAF2 (collectively "SDHx") are responsible for a large percentage of hereditary PCC/PGL and that SDHB mutations are strongly correlated with extra-adrenal tumor location, metastasis, and poor prognosis. Further, gastrointestinal stromal tumors and renal tumors are now associated with SDHx mutations. A PCC or PGL caused by any of the hereditary susceptibility genes can present as a solitary, apparently sporadic, tumor, and substantial numbers of patients presenting with apparently sporadic tumors harbor occult germline mutations of susceptibility genes. Current roles of pathologists are differential diagnosis of primary tumors and metastases, identification of clues to occult hereditary disease, and triaging of patients for optimal genetic testing by immunohistochemical staining of tumor tissue for the loss of SDHB and SDHA protein. Diagnostic pitfalls are posed by morphological variants of PCC/PGL, unusual anatomic sites of occurrence, and coexisting neuroendocrine tumors of other types in some hereditary syndromes. These pitfalls can be avoided by judicious use of appropriate immunohistochemical stains. Aside from loss of staining for SDHB, criteria for predicting risk of metastasis are still controversial, and "malignancy" is diagnosed only after metastases have occurred. All PCCs/PGLs are considered to pose some risk of metastasis, and long-term follow-up is advised.

Pigmented paraganglioma of the kidney: a case report

Paragangliomas are rare neoplasms arising from undifferentiated cells of the primitive neural crest. We report a case of a 57-year-old patient with renal pigmented paraganglioma that was an incidental finding. Histopathological examination showed typical morphology of paraganglioma, as well as the unusual feature of large amounts of pigment in the cytoplasm of the tumor cells which was confirmed by bleached Fontana-Masson. Electron microscopy showed abundant, pleomorphic electron-dense granules consistent with neuromelanin. The tumor cells were positive for CD56 and chromogranin A, negative for HMB-45. The unique morphologic appearance represents divergent differentiation from neural crest. To our knowledge, the present case represents the first example of pigmented paraganglioma of the kidney.

Miscellaneous Pseudotumors and Mesenchymal Tumors of the Female Genital Tract

Benign and malignant soft tissue tumors and pseudotumors can rarely arise anywhere in the female genital tract. Their pathologic features as well as behavior typically overlap with those described in tumors involving typical locations. However, due to their rarity, not infrequently these tumors represent a diagnostic challenge. Their diagnosis should be based on careful gross examination, thorough sampling, and morphologic evaluation, applying a selected immunohistochemical panel and molecular studies. Accurate classification of these tumors is important because their clinical behavior, prognosis, and therapy differ markedly. This article outlines several mesenchymal lesions reported in the female genital tract, encompassing recent histologic, immunohistochemical, and molecular findings, with special emphasis on problems in the differential diagnosis.

Melanotic paraganglioma arising in the temporal horn following Langerhans cell histiocytosis

Intracerebral paragangliomas are rare because of the lack of paraganglial cells in the cerebral tissue. We report a rare case of melanotic paraganglioma arising from the temporal horn of the lateral ventricle in a patient with prior Langerhans cell histiocytosis (LCH) treated with chemotherapy and radiation.

Paraganglioma of the Ovary

Paraganglioma is one of the rarest neoplasms to involve the ovary, whether primary or metastatic, with only two previous reports. We describe three examples that occurred in patients 22, 58, and 68 years of age. Two patients had hypertension. Two tumors involved the left ovary and one the right ovary; they ranged from 8 to 22 cm, were solid, and were tan, brown, or yellow. One tumor was confined to the ovary; in the second case, there were tumor deposits on the posterior surface of the uterus and the contralateral ovary; in the other case, there was peri-aortic lymph node involvement and peritoneal deposits. In all cases, however, radiologic investigations did not reveal an alternative primary site. On microscopic examination, all three tumors showed a predominantly nested "zellballen" pattern with groups of cells surrounded by a vascular stroma. Tumor cells largely had abundant granular eosinophilic cytoplasm with, in 2 cases, focal clear cell areas. In 1 case, bizarre tumor giant cells were present. Immunohistochemically, all neoplasms were cytokeratin negative and diffusely positive with neuroendocrine markers. In 1 case, there was an S-100-positive population of sustentacular cells. Two cases were positive for inhibin, one focal and one diffuse, and the other was focally positive for calretinin. Electron microscopy performed in 2 cases revealed dense core neuroendocrine granules. One patient has been followed up for 15 years and is alive and well. Although metastatic spread from an undetected primary outside the ovary cannot be totally excluded for the 2 cases with extraovarian disease, we think that the neoplasms most likely represent primary ovarian paragangliomas. Because various neoplasms in the sex cord-stromal and steroid categories are likely to enter into the differential diagnosis, inhibin and calretinin positivity represents a significant potential diagnostic pitfall. The differential is broad and may include many other ovarian tumors, particularly those with an oxyphilic cell type. Possible theories of histogenesis of primary ovarian paraganglioma include an origin from extra-adrenal paraganglia in the region of the ovary or unidirectional differentiation within a teratoma.

Composite paraganglioma-ganglioneuroma of the urinary bladder

Presented herein is the case of a 73-year-old man, complaining of dysuria, who had a composite paraganglioma-ganglioneuroma of the urinary bladder (CPGUB). At cystoscopy a submucosal tumor was found in the urinary bladder and resected after transurethral biopsy. The levels of serum catecholamine and 24 h urinary excretion of catecholamine and vanillylmandelic acid were elevated. Grossly, the resected tumor, measuring 4 x 3 x 2.5 cm, had a brownish cut surface with no necrosis and hemorrhage. Histologically, the tumor had alternating cellular and fibrous areas. The cellular areas consisted of polygonal cells, arranged in well-defined nests (Zellballen) and positive for Grimelius staining, with abundant amphophilic to acidophilic cytoplasm, occasionally containing eosinophilic hyaline globules and brown pigments. Although the nuclei of several polygonal cells were bizarre, mitoses and vascular invasion were not found. Fibrous areas consisted of spindle cells, resembling Schwann cell, admixed with ganglionic cells. To the authors' knowledge, only four cases of CPGUB have been reported in the English-language literature. Detailed reported cases and the present case showed no malignant features, such as extra-bladder infiltration and metastasis, and no recurrence in the short length of follow up. Accumulation of long-term follow-up cases may provide valuable prognostic information on this composite tumor.

Perivascular epithelioid tumor of urinary bladder and vagina

Perivascular epithelioid cell tumors are recently characterized neoplasms composed of large clear HMB-45-positive epithelioid cells arranged in an organoid pattern. The histogenesis of these neoplasms remain obscure. We report here 2 such tumors in young female patients aged 19 and 16 years involving the urinary bladder and vagina, respectively (in the absence of the tuberous sclerosis complex) . Microscopically, both tumors were composed of perivascularly arranged cells with granular eosinophilic fluffy cytoplasm, round-to-oval nuclei, and prominent nucleoli. Melanin pigmentation was present in the vaginal tumor. Immunohistochemically, both tumors strongly expressed HMB-45. They were negative for cytokeratin, vimentin, and S-100. The vaginal tumor recurred 10 months after resection and chemotherapy. The patient with the bladder tumor was lost to follow-up.

Pigmented “Black” Pheochromocytoma of the Adrenal Gland: A Case Report and Review of the Literature

A pigmented “black” mass was discovered incidentally in a 72-year-old woman. The tumor, which was detected near the upper pole of the left kidney, was cystic and intensely black throughout with the presence of abundant, coarse, dark brown to black pigment granules. Histologic examination showed a proliferation of monomorphous neoplastic cells arranged in a typical zellballen growth pattern. These features indicated a diagnosis of pheochromocytoma. Immunostains for chromogranin A, synaptophysin, and neuron-specific enolase were positive. The immunostain for HMB-45 was negative. Electron microscopy showed neurosecretory-type granules and larger pleomorphic granules, which were considered most consistent with neuromelanin, a waste product of catecholamine metabolism. The evidence of melanin or melanin-like pigment in the adrenal gland has been described in only 10 cases in the literature and is always a microscopic finding. The case reported here is unique for the characteristic black macroscopic appearance and the abundance of pigment.

Pigmented composite paraganglioma-ganglioneuroma of the urinary bladder

We report a case of a pigmented composite paraganglioma-ganglioneuroma of the urinary bladder in a 70-year-old female. Grossly, the tumor measured 6.5 cm in diameter and had arisen from the base of the urinary bladder. Histologically, the tumor was composed of approximately equal components of paraganglioma and ganglioneuroma, which were partly separated and partly mixed, and intermingled with each other. There were foci of ample dark brown pigmentation in the cytoplasm of chromaffin paraganglioma cells. The pigment was Masson-Fontana-positive and had been bleached by hydrogen peroxide (H2O2). Electron microscopy showed large, abundant, pleomorphic electron-dense granules consistent with neuromelanin. In addition, there were numerous electron-dense neurosecretory-type granules. Neuromelanin, melanin or lipofuscin are occasionally observed in paragangliomas, although the occurrence of these pigments has never been described in a composite tumor originating from either adrenal medulla or extraadrenal paraganglia. To the best of our knowledge, our report represents the first case of pigmented composite paraganglioma-ganglioneuroma and expands the morphological spectrum of these unusual tumors.

Ectopic neural and neuroendocrine neoplasms

Although neural and neuroendocrine tissues are distributed virtually ubiquitously throughout the body, the occurrence of selected neoplasms related to those lineages is extremely uncommon in some topographic sites. This review considers the clinicopathologic characteristics of heterotopic pituitary adenomas; neuroendocrine carcinomas in non-organ-based locations; ectopic (extraneuraxial) meningiomas and gliomas; visceral neuroblastic neoplasms and primitive neuroectodermal tumors; and paragangliomas arising outside the sympathoadrenal neural network. Practical approaches to differential diagnosis are emphasized.

Pigmented lesions in unusual anatomic sites

This review considers pigmented melanin-containing lesions arising in extracutaneous locations. It includes reactive lesions as well as benign and malignant neoplasms. Melanocytic lesions of the mucosae, nervous system, and individual organs are discussed, and rarer pigmented tumors in unusual sites are also covered. A brief description of the histology and clinical behavior along with proposed explanations for their ectopic location are provided. Emphasis is given to the reality that detailed morphological evaluation and application of ancillary techniques can establish the melanocytic nature and biologic potential of such tumors, but cannot, by themselves, determine the primary or metastatic nature of these lesions.

Paraganglioma of the vagina: report of a case, including immunohistochemical and ultrastructural findings

Paragangliomas are uncommon neoplasms of the female genital tract, with fewer than 15 reported cases arising from the uterus, ovary, vagina, and cervix. Three of these tumors presented in the vagina. This report describes the authors' experience with a paraganglioma of the vagina in a 24-year-old woman that presented as an asymptomatic mass. The histologic features in the initial biopsy proved again that the paraganglioma may be confused with other vascular neoplasms. The clinical course after the biopsy implied that this neoplasm had been awakened from its functionless dormancy.

Paraganglioma of the urinary bladder: a lesion that may be misdiagnosed as urothelial carcinoma in transurethral resection specimens

Paraganglioma of the urinary bladder is a rare tumor with characteristic histologic and immunohistochemical features. However, in our experience, it may be misdiagnosed as urothelial cancer because of 1) its frequent involvement of the muscularis propria; 2) morphology that may suggest urothelial cancer in transurethral resection specimens, particularly if there are artifactual changes induced by that procedure; 3) failure of pathologists to include it in their differential diagnosis when evaluating a bladder tumor; and 4) only a minority of the cases are associated with symptoms that might prompt consideration of the diagnosis. Distinction between paraganglioma and urothelial cancer is important because of likely different therapeutic options. In this report, we describe our experience with the histopathology of paragangliomas of the urinary bladder with emphasis on the histologic features that have led to their being misdiagnosed as conventional urothelial cancer and, most importantly, those that will help pathologists recognize this rare tumor of the bladder. Fifteen cases of paraganglioma of the urinary bladder were studied, 11 of them consult cases. They affected patients (8 male, 7 female) with a mean age of 49.5 years; only two had symptoms suggestive of the diagnosis, including hypertension during cystoscopy and episodic headache. Three consult cases were submitted with a diagnosis of "transitional cell carcinoma" and 4 with a diagnosis only of "bladder tumor." Histologically, "zellballen" and diffuse patterns were present in 12 (80%) and 3 (20%) of the cases. A delicate fibrovascular stroma was obvious in 14 (93%) cases. Other patterns included irregular nests and pseudorosette formation. Tumor necrosis, significant cautery artifact, and muscularis propria invasion were present in 1 (7%), 3 (20%) cases, and 10 (67%) cases, respectively. All 15 tumors were composed of large polygonal cells with abundant granular cytoplasm. Focal clear cells were present in 3 (20%). The nuclei were mostly uniform, although occasional pleomorphic nuclei were seen in 6 (40%) cases, and 2 (13%) had frequent pleomorphic nuclei. Mitoses were rare overall, and no abnormal mitotic figures were found. The major histologic features that led to misdiagnosis included a diffuse growth pattern, focal clear cells, necrosis, and muscularis propria invasion, with significant cautery artifact compounding the diagnostic problems. Immunohistochemically, 2 of 2 tumors were positive for neuron-specific enolase, 9 of 10 tumors for chromogranin, and 2 of 3 tumors for synaptophysin; 3 of 3 tumors were negative for cytokeratin and 1 of 1 tumor negative for HMB-45. Paraganglioma of the urinary bladder may be misdiagnosed as urothelial cancer, but a careful search for the characteristic histologic features and, if necessary, supportive immunohistochemical studies, should lead to a correct diagnosis.

Blue nevus of the endometrium

A 36-year-old woman with a long history of amenorrhea underwent endometrial curettage. An aggregate of short spindle cells containing a finely granular, dark brown pigment with the histochemical characteristics of melanin was detected in the endometrial stroma. This finding is considered analogous to the occurrence of similar cells in the endocervical stroma and is most appropriately designated a "blue nevus" of the endometrium. The occurrence of nonneoplastic, melanin-laden cells in the endometrial stroma is an extremely rare phenomenon, which has been reported only once previously.

The pigmented "black" neuroendocrine tumor of the pancreas: a question of origin

BACKGROUND

Pigmented neoplasms are extremely rare in the pancreas, and, when black pigment is identified, it often suggests the diagnosis of metastatic melanoma. The authors describe two patients with pigmented "black" neuroendocrine tumors of the pancreas. One patient had an incidental (0.5 cm) finding, and the second patient had a well-demarcated, 4.5-cm mass identified by computerized tomography that was consistent with an islet cell tumor.

METHODS

The two neoplasms were resected surgically and studied by light microscopy using hematoxylin and eosin (H&E), Fontana-Masson, and iron stains. The neoplasms were examined immunohistochemically, and ultrastructural analysis was performed.

RESULTS

H&E stains revealed nests of well-differentiated cells with small, round, centrally placed nuclei. The cytoplasm of the neoplastic cells was pink and granular and contained abundant brown-black pigment. Angiolymphatic and perineural invasion were identified in the larger neoplasm. Both neoplasms demonstrated a positive reaction with a Fontana-Masson stain, which was susceptible to bleaching, and a negative reaction to an iron stain. Immunohistochemical stains showed that neoplastic cells expressed chromogranin and synaptophysin but did not express HMB-45, S-100 protein, glucagon, or insulin. Ultrastructural examination revealed regular neurosecretory granules (100-150 nm) and large, irregularly shaped, electron-dense granules with small lipid inclusions consistent with lipofuscin.

CONCLUSIONS

These pigmented pancreatic neoplasms are similar histologically and radiographically to the "black adenoma" of the adrenal gland. It is important to recognize these tumors, because they may mimic metastatic melanoma.

Lessons to be learned: a case study approach. Paraganglioma of the urinary bladder

Primary paraganglioma arises infrequently in the urinary bladder. We present here the clinicopathological, immunohistochemical and ultrastructural findings in a 23-year-old Saudi female. She was hospitalised because of gross haematuria over the previous seven days. The intravenous urogram revealed a filling defect in the urinary bladder. Cystoscopy disclosed a non-papillary tumour arising from the roof of the bladder neck. Transurethral resection was, accordingly, performed--but marked fluctuation in blood pressure was observed during the procedure. The histopathological findings of trabeculae and small nests of plump oval to spindle cells with a clear to acidophilic cytoplasm, forming an organoid pattern and demonstrating inconspicuous mitotic activity, were diagnostic of paraganglioma of the urinary bladder, the diagnosis was confirmed by means of immunohistochemical and ultrastructural studies. The endocrine markers chromogranin A and neuron-specific enolase were positive in chief cells; sustentacular cells at the periphery of neoplastic cell clusters were positive for S-100 protein. Neurosecretory granules were identified by electron microscopic examination. It is emphasised that, currently, there are no anatomico-pathological criteria to distinguish benign and malignant forms of the disease. Post-surgical recovery was uneventful in this case. Recurrence and metastases, though infrequent, have been reported in the literature; therefore, radiation therapy may be an important adjunct--and long-term follow-up is mandatory.

Abdominopelvic sarcoma of perivascular epithelioid cells. Report of four cases in young women, one with tuberous sclerosis

The perivascular epithelioid cell has been proposed to be the unifying proliferating cell type in a number of lesions such as angiomyolipoma, lymphangiomyomatosis, clear cell "sugar" tumor and renal capsuloma. With the exception of rare examples of angiomyolipoma, they are non-metastasizing. We report four examples of a new member of this family of perivascular epithelioid cell neoplasms that occur in abdominopelvic location and show metastatic properties. The patients, all women, were aged 19 to 41 years (mean, 32), and presented with a tumor mass involving the serosa of the ileum, uterus or pelvic cavity. Morphologically, the tumors were composed of sheets of large polygonal cells with glycogen-rich clear or eosinophilic cytoplasm and moderately pleomorphic nuclei, traversed by a delicate vasculature, mimicking clear cell carcinoma. There were areas of coagulative necrosis and occasional mitotic figures. Intracytoplasmic brown pigment was present in two cases. Spindly cells, smooth muscle and fat were absent. Lymphovascular invasion was present in all, lymph node metastasis was documented in two and metastasis to the ovary was present in one case. Two patients developed widespread metastatic disease after 10 and 28 months from diagnosis. One patient showed the clinical signs of tuberous sclerosis. In spite of the epithelial-like appearance, the tumor cells were negative for epithelial markers but were strongly positive with the melanogenesis-related marker HMB45. Another melanogenesis marker (MART-1) was positive in two cases. Other markers including S-100 protein, vimentin, muscle-specific actin, desmin and chromogranin A were negative. Thus, these tumors are not readily classifiable in the existing schema of known entities, and show overlapping morpho-phenotypic features of clear cell "sugar" tumor of the lung and epithelioid angiomyolipoma. We consider them as sarcomas composed of a pure population of uncommitted perivascular epithelioid cell, that lack modulation toward smooth muscle or adipose cells.

Uterine carcinosarcoma with melanocytic differentiation

A 65-year-old black woman was found to have a 3.0 cm endometrial tumor that was a carcinosarcoma with a major epithelial and a less prominent mesenchymal component. The latter was undifferentiated but one focus of chondroid differentiation was noted. The former showed papillary serous differentiation. Melanin pigment was observed in both epithelial and mesenchymal components. Staining with antisera to S100 protein and HMB-45 confirmed the presence of melanocytes. An endocervical focus of tumor also contained melanin. Electron-microscopic studies showed large tumor cells with an irregularly indented nucleus and abnormal giant cytoplasmic melanosomes. Only one case of uterine carcinosarcoma with melanocytic differentiation has been previously reported.

Clear cell sarcoma arising in the transverse colon

A case of clear cell sarcoma (CCS) arising in the transverse colon is presented. The tumor consisted of sheets or small nests of epithelioid malignant cells possessing pleomorphic nuclei with one or more prominent nucleoli and ample clear or slightly eosinophilic cytoplasm. Some of the tumor cells contained various amounts of melanin pigments that were confirmed by histochemical and ultrastructural examinations. Immunohistochemical examination showed a positive immunoreactivity for HMB45 and S-100 protein. A metastatic nodule, which was found 9 months after surgery, showed similar histological findings to those of the primary one but lacked melanin pigments. Reverse transcriptase- polymerase chain reaction using total ribonucleic acid obtained from metastatic nodule demonstrated the presence of EWS-ATF-1 fusion gene. Based on these findings, the present case tumor is a CCS of the colon.

Abnormal pigmentation of schwannoma attributed to excess production of neuromelanin-like pigment

Five cases of non-melanotic pigmented schwannoma with excess accumulation of neuromelanin are presented. The tumors were composed basically of spindle or fusiform tumor cells, compatible with those of classical schwannoma, together with varying numbers of tumor cells containing various amounts of light brown or grayish pigment. Fontana-Masson stain demonstrated argentaffin granules in some tumor cells of each tumor and bleaching with potassium permanganate abolished argentaffin reaction. Ultrastructural examination demonstrated the granules contained fine particles with heterogeneous density, occasionally together with coarse granular materials or amorphous high-density areas, indicating lysosome or autophagosome. Neither typical melanosomes nor neurosecretory granules were detected. In immunohistochemistry, neurogenic markers as well as CD68 were expressed in most tumor cells in each case and various numbers of tumor cells were positive for Leu7 and CD34. Lysozyme was also frequently positive in tumor cells, especially in granular cells. HMB45 was not expressed in any of the cases. These findings indicate that these cases are schwannomas with abnormal accumulation of neuromelanin-like pigment.

Pigmented ("black") extraadrenal paraganglioma

A pigmented ("black") extraadrenal paraganglioma was discovered incidentally in a 57-year-old woman during ultrasonography. The tumor was located in the retroperitoneum near the superior border of the right kidney. Results of preoperative fine-needle aspiration and intraoperative frozen sectioning of the resected jet-black tumor (13 cm in diameter, 225 g) were both interpreted as suspicious for malignant melanoma. Histomorphology and immunohistochemistry were diagnostic for paraganglioma. Electron microscopy showed numerous dense-core neurosecretory-type granules, as well as abundant, larger pleomorphic electron-dense granules; most were consistent with lipofuscin or neuromelanin. No melanosomes or premelanosomes were identified. Histochemical stains showed that the pigment most likely is neuromelanin, a nonenzymatic or oxidative waste product of catecholamine metabolism. Eighteen other examples of pigmented paragangliomas have been reported in various sites in the English literature during the last 12 years; most indicate the presence of melanosomes or premelanosomes using electron microscopy, whereas in a minority of cases the pigment has not been characterized rigorously. Common embryogenesis from neural crest may help explain the overlapping phenotype of melanocytes and cells of paraganglioma.

Primary melanoma of the lung: a clinicopathologic and immunohistochemical study of eight cases

Primary malignant melanoma of the lung (PMML) is an uncommon neoplasm that may be confused with more conventional types of lung cancer. Although the previously proposed criteria for diagnosis, including the presence of an in situ component, are often difficult to satisfy, this lesion is characterized by a poor prognosis, ultimately leading to patient death. We report eight cases of PMML that presented as solitary, central endobronchial neoplasms, resulting in a picture that closely resembled carcinoid tumor or poorly differentiated non-small-cell carcinoma of the lung. The mean age at diagnosis was 51 years (range 45-71). The patients included one woman and seven men. The histologic growth pattern varied from organoid to fascicular and included epithelioid to spindled cells with hyperchromatic to vesicular nuclei, prominent eosinophilic nucleoli, and abundant eosinophilic to clear cytoplasm with occasional intranuclear cytoplasmic inclusions. A bronchial in situ component was present in four cases. Initial interpretations included carcinoid tumor, non-small-cell carcinoma, and malignant melanoma. Melanin was present in all neoplasms on hematoxylin and eosin staining, although very focally in one case, and was Fontana-Masson positive in all cases. Immunohistochemically, diffuse strong positivity for S-100, HMB-45, and vimentin was present in all seven tumors tested. All seven tumors were negative for cytokeratin, CAM 5.2, and chromogranin. Ultrastructural examination of the eighth case showed dysmorphic premelanosomes but no neurosecretory granules. None of the patients had disseminated disease at presentation, and all patients underwent surgical resection (seven lobectomies and one excision). In this series, primary malignant melanoma of the lung was characterized by an aggressive postoperative course, with five patients dying of metastatic disease from 4 to 32 months after resection (median 14 months). Two patients are alive with metastatic disease at 4 and 30 months after surgery, and the eighth patient is alive with no evidence of disease 108 months after surgery at last follow-up. Metastatic melanoma was identified in various sites, including the lungs, adrenal glands, liver, mesentery, brain, and bone. The cases herein presented indicate that PMML should be included in the differential diagnosis of primary bronchial tumors.

Pigmented extraadrenal paragangliomas. A clinicopathologic and immunohistochemical study of five cases

BACKGROUND

Pigmented extraadrenal paragangliomas are unusual neoplasms that have rarely been reported in the literature.

METHODS

The clinical, pathologic, and immunohistochemical features of five cases of pigmented extraadrenal paragangliomas were reviewed.

RESULTS

The patients were 2 women and 3 men within the ages of 17 and 56 years (mean age: 36.5). Two neoplasms were located in the lumbar spine, one in the urinary bladder, one in the anterior mediastinum, and one in the retroperitoneum. Clinically, one patient with spinal paraganglioma presented with symptoms of numbness and weakness of the lower extremities whereas the second patient had low back pain of several weeks' duration. The paraganglioma of the bladder occurred in a pregnant woman who had symptoms of dysuria and microscopic hematuria whereas the patient with an anterior mediastinal tumor presented with chest pain. No clinical history was obtained from the patient with the retroperitoneal tumor. None of the patients had a history of hypertension. Grossly, the tumors were described as well-circumscribed, soft, and slightly hemorrhagic, and measured from 2 to 9 cm in greatest dimension. Histologically, the five tumors displayed characteristics similar to those described in these tumors, mainly the presence of an organoid or zellballen growth pattern. In addition, they contained moderate amounts of intracellular melanin pigment that focally obscured the true nature of the lesion. Immunohistochemically, four cases were positive for chromogranin whereas S-100 protein was detected in the sustentacular cells in four cases. Follow-up information ranging from 6 months to 18 years for 3 patients revealed that the patients were alive and well without recurrence or metastasis. One patient with spinal paraganglioma was lost to follow-up, and the patient with mediastinal paraganglioma was a recent case and therefore the behavior of the paraganglioma could not be assessed.

CONCLUSIONS

The current study expands the morphologic spectrum of extraadrenal paragangliomas and emphasizes the need to consider these tumors in the differential diagnosis of pigmented neoplasms. These findings suggest that the presence of melanin pigment does not alter the behavior of these neoplasms.

Laryngeal mucosal malignant melanoma. A clinicopathologic, immunohistochemical, and ultrastructural study of four patients and a review of the literature

BACKGROUND

Primary laryngeal mucosal malignant melanomas are uncommon tumors that morphologically are readily confused with more common types of laryngeal cancer.

METHODS

Four cases of primary laryngeal mucosal malignant melanoma were identified from the files of the Otolaryngic Tumor Registry-Armed Forces Institute of Pathology. Clinical records were available for all four cases. Paraffin blocks or unstained slides were available for three of the four cases. The light microscopic features were evaluated in all cases. Immunohistochemistry was performed in three cases; electron microscopic analysis was performed in two cases. Follow-up data was available in three of the four cases.

RESULTS

The patients were all males and ranged in age from 35 to 84 years. The clinical presentations included hoarseness, hemoptysis, dysphagia, and airway obstruction, with complaints ranging from 1 to 8 months. The sites of involvement included the supraglottic larynx and the right true vocal cord. A history of cutaneous melanoma or of a melanoma of another site was not reported for any of the patients. Histologically, the tumors were invasive and composed of a pleomorphic epithelioid cell population of malignant cells. Malignant spindle-shaped cell could also be identified. The presence of melanin was identifiable by light microscopy in two cases; Fontana stains confirmed the presence of melanin in the other two. The immunohistochemical findings showed diffuse immunoreactivity with S-100 protein and HMB-45. There was no immunoreactivity with cytokeratin. The specimen of one patient demonstrated focal immunoreactivity with chromogranin. Electron microscopic features included the presence of premalonosomes or melanosomes. Total laryngectomy was the treatment of choice supplemented with radiotherapy. Follow-up information was available for three patients and all three died of metastatic disease within 36 months of diagnosis. Metastasis occurred to the brain, lungs, spine, and regional lymph nodes. The fourth patient was lost to follow-up.

CONCLUSIONS

Laryngeal mucosal malignant melanoma is an uncommon neoplasm that clinically and pathologically simulates more conventional types of laryngeal cancers. The light microscopic, immunohistochemical, and electron microscopic findings confirm the diagnosis. Aggressive management is indicated, as these tumors disseminate widely and are rapidly fatal.

Melanotic paraganglioma of the posterior mediastinum

A melanotic paraganglioma occurred in a 57-year-old woman, located in the left paravertebral space of the upper mediastinum. It was totally resected. During a 5 year follow up period neither tumour recurrence nor metastasis were observed. Histological examination of the tumour revealed a paraganglioma with monomorphous chief cell like elements which were arranged in a "zellballen" pattern. Immunohistochemical results also were in accordance with the diagnosis since neuron-specific enolase, chromogranin and synaptophysin were found in tumour cells whereas keratin was not. Additionally, neurosecretory granules were found in tumour cells during electron microscopy. A peculiar feature of the tumour was its strong pigmentation due to melanin located within the tumour cells and tumour associated melanophages. The simultaneous expression of functional properties of two different neural crest derived cells in one tumour stresses the close relationship between all neural crest elements and is in accordance with the observation of other melanotic, non-melanomatous tumours.

Peripheral carcinoid tumor of the lung with focal melanin production

A case of carcinoid tumor of the lung with focal melanin production was encountered in a 56 year old Japanese woman. The tumor was found 16 years previously by mass survey chest X-ray and had enlarged two-fold in the intervening period. The tumor consisted of a variety of tumor cells showing a spindle, polygonal and pleomorphic appearance with abundant vasculature in the stroma. All tumor cells showed argyrophilia, together with a few showing argentaffinity. Melanin-containing tumor cells were also present in parts. Ultrastructurally, most tumor cells possessed various numbers of neurosecretory granules and a few of them contained granular type melanosomes. Tumor cells were connected with desmosomes and a few of them contained tonofilament-like microfilaments. Only a few contained both neurosecretory granules and melanin. By immunohistochemistry, serotonin, met-enkephalin and beta-endorphin positive cells were observed scattered throughout the tumor. A few tumor cells positive for tyrosine hydroxylase were also detected. Additionally, most tumor cells were positive for keratin. On the basis of these findings, the tumor of the current case is a pulmonary carcinoid tumor with focal melanin production.

Primitive neuroectodermal tumors of the uterus: a report of four cases

Four cases of primitive neuroectodermal tumor (PNET) of the uterine corpus are reported, bringing the total number of reported PNETs in this site to seven. The four women were in their seventh decade of life and presented with abnormal vaginal bleeding and, in two cases, an enlarged uterus. The patients underwent total or subtotal abdominal hysterectomy and bilateral salpingo-oophorectomy and, in one patient, pelvic lymphadenectomy. Three patients received postoperative radiation therapy, chemotherapy, or both. Gross examination revealed fleshy polypoid masses filling the endometrial cavity and, in two cases, deeply invading the myometrium. Histologic, immunohistochemical, and, in two cases, ultrastructural examination revealed typical PNETs that exhibited variable degrees of neural, glial, ependymal, and medulloepithelial differentiation. Two PNETs were admixed with other neoplasms: in one case a grade I endometrial adenocarcinoma and in the other a low-grade endometrial stromal sarcoma. The prognosis of the tumors was related to their stage: two patients with stage I tumor were alive with no evidence of disease at 5 and 6 years, whereas two patients with stage III or IV tumor died of tumor at 6 and 12 months. Although it has been suggested that uterine PNETs may be derived from displaced germ cells or implanted fetal tissues, evidence provided by this study, including the advanced ages of the patients and an admixture with neoplasms of unquestioned müllerian origin, suggests a müllerian origin for these tumors in at least some cases.

Malignant paraganglioma of the uterus

We report a malignant uterine paraganglioma in a 40-year-old female, who died 7 months after the initial diagnosis. On light microscopy the tumour showed a typical zellballen pattern as well as a pronounced cellular pleomorphism. In many tumour cells hyaline globules were demonstrated within the cytoplasm. Immunohistochemically the lesion was characterized by the presence of neuron-specific enolase, protein gene product 9.5 and synaptophysin, and electron microscopically by the occurrence of neurosecretory granules.

Melanotic cerebral ganglioglioma: evidence for melanogenesis in neoplastic astrocytes

A composite melanotic glial-ganglionic tumor was resected from a 17-year-old girl who presented with a 5-year history of epilepsy. Grossly, the tumor was partly cystic, partly solid, located superficially in the temporal lobe. Histologically, its glial component was composed of spindle and pleomorphic cells, including tumor giant cells, which were associated with Rosenthal fibers, eosinophilic granular bodies and marked desmoplasia. The cells had immunohistochemical and ultrastructural features of astrocytes, and some were invested by incomplete basal lamina. Thus, the tumor had many features in common with pleomorphic xanthoastrocytoma. However, its most striking feature was the presence of melanin pigment in numerous neoplastic cells. Immunoelectron microscopy revealed glial fibrillary acidic protein-positive intermediate filaments in tumor cells bearing melanosomes and premelanosome, proving their astrocytic nature. This case demonstrates, for the first time, melanosomal melanogenesis in human cells with astrocytic phenotype, and provides additional evidence for the ability of central neuroepithelial cell derivatives to produce melanin.

Alveolar soft-part sarcoma of the uterine corpus: histological, immunocytochemical and ultrastructural study of a case

A case of alveolar soft-part sarcoma located in the uterine corpus is reported. It was an incidental finding in the hysterectomy specimen of a 40-year-old woman. Light and electron microscopic examination revealed periodic-acid-Schiff-positive, diastase-resistant, membrane-bound cytoplasmic granules and crystalloids. Tumour cells expressed immunoreactivity with vimentin, desmin, cytokeratins, NK1/C3 and HMB-45 antibodies. Four years postoperatively, the patient is still alive without evidence of disease. Differential diagnoses, immunocytochemistry and clinical management of uterine alveolar soft-part sarcoma are discussed and the literature reviewed.

Melanotic paraganglioma of the orbit: a case report

A paraganglioma of the orbit in a 21-year-old woman is presented, containing oculo-cutaneous melanin in many tumor cells, occasionally adjacent to neurosecretory granules, and in macrophages. This tumor expands the list of neuroectodermal tumors with potential melaninization.