1/19. Malignant myoepithelioma of the vulva resembling a rhabdoid tumour.AIMS: We report an example of malignant myoepithelioma of the vulva, which has not been hitherto described. We discuss the differential diagnosis and briefly review the literature. methods AND RESULTS: The lesion was found in an 81-year-old woman as an indolent 40 mm tumour. The neoplastic cells showed a myoid, spindled, epithelioid and plasmacytoid phenotype. Hyalinization of extracellular material and myxoid changes were present. There was a partly solid and microcystic pattern and a tight cohesiveness of cells was lacking. The circumscribed multinodular tumour somewhat resembled an extrarenal rhabdoid tumour, having large tumour cells with prominent nucleoli and large amounts of acidophilic cytoplasm. Immunohistochemically, the tumour cells were immunoreactive for cytokeratin, vimentin, muscle-specific actin, alpha-smooth muscle actin, and S100 protein, but not for desmin, epithelial membrane antigen, factor viii-related antigen, CD34 and CD31. CONCLUSIONS: The histological and cytomorphological appearance of the tumour well as the immunohistochemical findings suggest the diagnosis of malignant myoepithelioma, possibly derived from minor vestibulary glands or ectopic breast tissue. Differential diagnoses are, in particular, extrarenal rhabdoid tumour and 'proximal type' epithelioid sarcoma. Differentiation is important, because the tumours show a different behaviour and prognosis.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
2/19. myoepithelioma of the lacrimal gland: report of a case with potentially malignant transformation.myoepithelioma of the lacrimal gland is extremely rare and only four cases, one of which was malignant, have been reported in detail. The present report describes a case of lacrimal gland myoepithelioma in a Japanese male with histological features suggestive of potentially malignant transformation. The excised tumor consisted of two components, a central nodular component and a peripheral component surrounding the former. These components were separated by a fibrous tissue. Microscopically, both components were comprised almost entirely of spindle-shaped cells, but with some epithelioid cells containing glycogen granules. Extracellular spaces in the peripheral component were filled with eosinophilic materials with the occasional crystalloid structures, which were immunoreactive for collagen type i. Neoplastic cells were immunoreactive focally for vimentin and S-100, but negative for cytokeratins, epithelial membrane antigen, muscle actin, smooth muscle actin, desmin, myosin, and glial fibrillary acidic protein. The neoplastic cells in the central component showed nuclear pleomorphism and atypia with a higher frequency of mitotic figures, and higher labelings of proliferation markers than those in the peripheral component. Neither invasion, necrosis, nor hemorrhage was observed in the tumor. From these findings we proposed a diagnosis of potentially malignant myoepithelioma.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
3/19. Mixed tumors, myoepitheliomas, and oncocytomas of the soft tissues are likely members of the same family: a clinicopathologic and ultrastructural study.Four diagnostically unusual soft tissue tumors are presented. All lesions were of consistent size and long duration. Histologically, one lesion was analogous to mixed tumors of the usual sites (i.e., salivary glands), one lesion was totally spindled, and the two other lesions both had oncocytic appearances (epithelioid and spindle biphasic pattern in a case, purely epithelioid in the other). Immunohistochemically, the mixed tumor was positive for vimentin, cytokeratins, S-100 protein, and focally for EMA. The purely spindled tumor exhibited immunoreactivity for vimentin, actins, S-100 protein, EMA (focally), and GFAP. The oncocytic biphasic tumor was positive for mitochondrial antigen, vimentin, and actins. The purely epithelioid oncocytic neoplasm was immunoreactive only for mitochondrial antigen and vimentin. Ultrastructurally, in the epithelial-like portion of the first (mixed) tumor, peripheral arrays of contractile filaments were detected along with well-developed desmosomes. In the second (spindled) case, peripheral contractile filaments and attenuated desmosomes were also seen. In the third case, a huge number of mitochondria, some desmosomes, and actin-type microfilaments were found. In the fourth case, desmosomes and punctate subplasmalemmal densities, in addition to numerous mitochondria, were documented. In all cases an external basal lamina were present, which was discontinuous in the first three cases and almost continuous in the fourth. These tumors were respectively designated as mixed tumor, myoepithelioma of the classic type, myoepithelioma of oncocytic type with biphasic cell architecture, and true oncocytoma. So far, all tumors have followed benign clinical courses (median follow up: 12 months). Comparisons with similar tumors of other sites are drawn, and suggestions for considering all of them as members of the same myoepithelial-derived tumor family are given.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
4/19. Soft tissue myoepithelioma: a case report.Myoepitheliomas are tumours composed predominantly or exclusively of myoepithelial cells. They are well described, especially within the salivary gland, but their occurrence in soft tissues is less well known and this often results in diagnostic problems. We report a case involving the deep soft tissues of the lower neck behind the clavicle. Grossly, the tumour was well circumscribed with solid and cystic areas. histology showed a richly vascularised tumour composed of bland round, ovoid or spindle-shaped cells. Various growth patterns were present including solid, nested, microcystic and trabecular arrangements. In some areas there was an alveolar pattern with tumour cells lining fibrous septae. immunohistochemistry showed diffuse strong positivity for S100 protein, calponin, vimentin and glial fibrillary acidic protein and focal positivity for epithelial membrane antigen, 34betaE12 and AE1/AE3, in keeping with myoepithelial differentiation. Electron microscopy revealed tumour cells surrounded by basal lamina with subplasmalemmal densities and containing cytoplasmic myofilaments. This case report highlights the rare occurrence of myoepitheliomas in deep soft tissues. Pathologists should be aware of this and should consider a myoepithelioma in the differential diagnosis of a soft tissue spindle cell neoplasm.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
5/19. Massive infra-clinic invasion of the facial nerve by a myoepithelial carcinoma of the parotid.We report a new case of myoepithelial carcinoma of the parotid gland in an 8-year-old girl. This is the first case published in a child. The parotid tumour was slightly tender and measured almost 2 cm in diameter. There was no associated facial nerve paralysis despite surgical and histologic evidence of massive facial nerve infiltration. We performed total parotidectomy with resection of the intra-mastoid portion of the facial nerve completed with prophylactic lymph node dissection. Eight months after surgery, MRI revealed a deep-lying recurrence, which required reintervention. There has been no subsequent recurrence 18 months after surgery. Microscopic examination of operative specimens confirmed the diagnosis of parotid myoepithelial carcinoma with fusiform cells. Immunohistochemical markers were positive for cytokeratin, epithelial membrane antigen, smooth muscle actin, S-100 protein, anti-desmine and anti-vimentine. This difficult to diagnose tumour, which was individualised by the world health Organisation in 1991, is considered a moderate to high-grade malignancy when it develops in a pleomorphic adenoma or appears de novo.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
6/19. myoepithelioma of the vulva.The histologic diagnosis of myoepithelioma is often problematic. We here describe a case of myoepithelioma, composed exclusively of neoplastic myoepithelial cells, in the vulva of a 52-year-old female. The vulva is a very rare site for this neoplasm. A subcutaneous tumor measuring 3.0 x 2.5 x 2.0 cm displayed a multinodular growth pattern. Histologically, it was characterized by epithelioid, trabecular, cord, solid, or reticular arrangements of tumor cells and markedly hyalinized stroma. The tumor cells were large and polygonal with eccentrically located round to oval nuclei with prominent nucleoli and eosinophilic cytoplasm. Some cells had clear cytoplasm. Moderate cellular atypia was seen and there were 4 mitotic figures per 10 high-power fields. No ductal architecture was found and there were no areas of chondroid or osseous differentiation. There was no destructive invasive growth. Immunohistochemically the tumor was positive for vimentin, epithelial membrane antigen, wide keratin, alpha-smooth muscle actin, S-100 protein, and glial fibrillary acidic protein. The patient was well and free of disease at 6 months. This neoplasm should be distinguished from other epithelial and mesenchymal neoplasms as it shows a different clinical behavior.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
7/19. Clear cell myoepithelial carcinoma of the breast: a case report.Primary clear cell myoepithelial carcinoma (CCMC) is extremely rare. During the past twenty years, only one CCMC case has been reported. Here, a case of CCMC is reported. A 30-year-old woman became aware of an abnormal mass on the left breast, and quadrantectomy was performed. Microscopically, it consisted of tumor cells that had clear cytoplasm and showed an invasive growth pattern. Immunohistochemically, the tumor was positive for alpha-smooth muscle actin, S-100, partly positive for vimentin and epithelial membranous antigen. From these findings, the tumor was diagnosed as CCMC. Most of the clear cell myoepithelial tumors are probably misclassified in other examples. It is expected that the numbers of CCMC may be increased by routinely performing special stains and immunohistochemical stains, even without ultrastructual study.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
8/19. Intraductal growth of malignant mammary myoepithelioma.This report describes the histologic and immunohistologic features of an intraductal myoepithelial tumor that developed in the breast of a 61-year-old woman. Histologically, the tumor proliferated intraductally, with both a comedo or doughnut pattern and a solid pattern containing narrow fibrovascular cores, mimicking what appeared to be a conventional intraductal carcinoma. No fine papillary or arborizing growth or cribriform formation was observed. Tumor cells at the ductal peripheral zone were polygonal and clear with abundant glycogen in the cytoplasm; they were transformed into nonclear cells with slightly eosinophilic cytoplasm toward the center of the involved ducts. Occasionally, nonclear cells were elongated, with a centrally located cigar-shaped nucleus. These elongated or spindle cells tended to show a fascicular and streaming pattern similar to that of a smooth muscle tumor. Immunohistochemically, alpha smooth muscle actin (alpha-SM-actin) and S-100 protein were expressed in most of the nonclear cells. While clear cells also had a positive reaction for S-100 protein, they were mostly negative or barely positive for alpha-SM-actin. Epithelial membrane antigen (EMA) was also positive in a certain number of polygonal cells. These results support the myoepithelial nature of the present tumor, and some cells might also be immunologically differentiated into ductal epithelial cells. In addition to cytological atypia, frequent mitoses, and central necrosis within ducts, there was a minimal but evident stromal invasion, suggesting histological malignancy in this peculiar tumor.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
9/19. Malignant myoepithelioma of the salivary gland--an untypical clinical course.A case of malignant tumor developing from myoepithelial cells (malignant myoepithelioma) is presented. The primary focus was located in the region of the left submandibular salivary gland. A relapse and metastases were disclosed in the same salivary gland, in the lung and the left breast. Immunohistochemical studies demonstrated positive reactions for S-100 protein, cytokeratins, smooth muscle actin, vimentin, GFAP protein, p53 protein and ki-67 antigen, and allowed for establishing the final histopathological diagnosis of malignant myoepithelioma.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
10/19. myoepithelioma of the parotid gland initially diagnosed by fine needle aspiration cytology and immunocytochemistry: a case report.BACKGROUND: myoepithelioma is a rare, benign tumor of the salivary gland, most commonly affecting the parotid gland. Although the cytologic features of myoepithelioma are documented in a few case reports, it has rarely been diagnosed preoperatively by fine needle aspiration (FNA) cytology. CASE: A 33-year-old man presented with a left parotid swelling 2.5 cm in diameter and of about 5 years' duration. FNA smears showed bundles of spindle-shaped cells as well as plasmacytoid and stellate cells in sheets and dissociated forms. A few cells had nuclear grooves, and occasional cells showed intranuclear cytoplasmic inclusions. In May-Grunwald-Giemsa-stained smears, most of the cells had reddish cytoplasm. Red to purple, myxoid matrix was present as a scanty fibrillar substance and as globules surrounded by tumor cells vaguely reminiscent of adenoid cystic carcinoma. A cytodiagnosis of myoepithelioma was given and corroborated by immunocytochemical staining, which revealed a positive reaction for vimentin, smooth muscle actin and S-100 protein. Epithelial membrane antigen yielded a negative reaction except for a few plasmacytoid cells with weakly positive staining. Histopathology of the resected tumor and immunohistochemical staining confirmed the cytodiagnosis of myoepithelioma. CONCLUSION: FNA cytologic features together with immunocytochemical studies on smears can offer a preoperative diagnosis of myoepithelioma.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
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