1/132. Fine-needle aspiration cytology of polymorphous low-grade adenocarcinoma of the tongue.The cytologic features derived from a fine-needle aspiration of polymorphous low-grade adenocarcinoma (PLGA) of the base of the tongue are described. The tumor cells were composed of cuboidal epithelial cells and short, spindle-shaped myoepithelial-like cells, and they formed large cell clusters. In the central portion of the clusters, myxoid materials were present, and palisading tumor cells occasionally surrounded them. Histological examination revealed solid proliferation of the epithelial cuboidal and spindle cells. The former frequently formed tubular and papillary structures. The tumor was not encapsulated, and invasion of adjacent muscle tissue was noted. Although the cytologic differentiation from cellular variants of pleomorphic adenoma and myoepithelioma is difficult, the feature of palisading tumor cells may be useful in the differential diagnosis.- - - - - - - - - - ranking = 1keywords = spindle cell, spindle, cell (Clic here for more details about this article) |
2/132. Malignant myoepithelioma of the salivary glands: clinicopathological and immunohistochemical features.Malignant myoepitheliomas (myoepithelial carcinomas) are uncommon, and we know of only 29 reported cases. We present a new case together with its clinical, histological, and immunohistochemical features. The tumour was located in the inferior vestibular sulcus of a 64-year-old woman. She was treated by wide local resection. Malignant myoepitheliomas are distinguished from benign myoepithelial neoplasms by their infiltrating and destructive growth. The tumour cells may be spindle-shaped or more rounded (plasmacytoid cells) and contain cellular pleomorphism and mitotic activity. The clinical and biological behaviour of this tumour is not yet known and there is little information about treatment and prognosis.- - - - - - - - - - ranking = 0.24252970083028keywords = spindle, cell (Clic here for more details about this article) |
3/132. 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 = 0.27157512621143keywords = spindle, cell (Clic here for more details about this article) |
4/132. Myoepitheliomas of the skin and soft tissues. Report of 12 cases.We describe 12 cutaneous and soft tissue myoepitheliomas, most of them in elderly patients. Morphologically the cutaneous and soft tissue myoepitheliomas revealed the same spectrum as their salivary gland counterparts. They were composed of a mixture of spindle, epithelioid and clear myoepithelial cells. Immunohistochemically they were positive to keratins and S-100 protein and reacted inconsistently with antibodies to smooth muscle actin. Morphologically they lacked any folliculo-sebaceous or apocrine differentiation. We believe that they are related to the eccrine type of cutaneous mixed tumours. Most cases had a benign behaviour, but 1 tumour metastasized, and the patient died of the tumour. Myoepitheliomas of soft tissues should be distinguished from other neoplasms with epithelial differentiation and from ossifying fibromyxoid tumour of soft parts, parachordoma and extraskeletal myxoid chondrosarcoma.- - - - - - - - - - ranking = 0.21348427544913keywords = spindle, cell (Clic here for more details about this article) |
5/132. myoepithelioma of the gingiva. Report of a case.myoepithelioma is a rare form of salivary gland tumor composed entirely of myoepithelial cells. It represents about 1 to 1.5% of all salivary gland tumors and is most frequently located in the parotid. The authors present a case of myoepithelioma of the gingiva. The tumor presented a focal strong positivity for cytokeratins, a diffuse positivity for S-100 protein, and a rare focal positivity for actin. No duct formation was observed. myoepithelioma must be differentiated from several benign and malignant epithelial and mesenchymal tumors.- - - - - - - - - - ranking = 0.014522712690575keywords = cell (Clic here for more details about this article) |
6/132. cytogenetic analysis of a primary salivary gland myoepithelioma.myoepithelioma, a rare benign salivary gland neoplasm, is a tumor composed entirely of myoepithelial cells. Unlike pleomorphic adenoma, these tumors lack any ductal epithelial differentiation, and manifest a minor stromal element. Previous cytogenetic and molecular genetic studies have mainly investigated pleomorphic adenomas and reported recurring specific chromosomal alterations at 8q12 and 12q13-q15 regions. The cell origin of these alterations, however, remains speculative. We report the cytogenetic analysis of a parotid myoepithelioma and discuss the putative origin for the cells with cytogenetic alterations. Our analysis shows 12q12 involved in a translocation with a previously unreported partner (1q), and nonrandom del(9)(q22.1q22.3) and del(13)(q12q22). Our results indicate that the myoepithelial cell is the source of those cells with chromosomal alterations, and that myoepithelioma shares 12q alterations reported in a subset of pleomorphic adenomas.- - - - - - - - - - ranking = 0.072613563452873keywords = cell (Clic here for more details about this article) |
7/132. myoepithelioma of soft tissue.A myoepithelioma occurred in the subcutaneous tissue of the right shoulder of a 28-year-old man. The well-demarcated nodular tumor (3. 0 x 2.8 cm) was located in the subcutaneous tissue with no adhesion to the deltoid muscle. The tumor was composed of a fascicular proliferation of spindle cells with variable amounts of stroma and showed areas of sheets of epithelioid cells. In most areas, the tumor cells had uniform nuclei, but pleomorphic epithelioid cells were focally present. Mitotic activity was three per 10 high-power fields. No ductular structure was found throughout the tumor. Immunohistochemical and ultrastructural studies confirmed the myoepithelial origin of the tumor cells. The occurrence of myoepithelioma in the subcutaneous tissue has been rarely reported. Even though the tumor showed no aggressive behavior on the 2-year follow-up, it is still too early to comment definitely on the behav- ior of myoepithelioma of the subcutaneous tissue. This case provides further information about soft tissue myoepithelioma.- - - - - - - - - - ranking = 0.75747029916972keywords = spindle cell, spindle, cell (Clic here for more details about this article) |
8/132. Malignant myoepithelioma of the breast metastasizing to the jaw.A breast tumor in a 52-year-old female was interpreted as a malignant myoepithelioma based on morphological and immunohistochemical studies. The tumor consisted of elongated cells with clear cytoplasm and lacked glandular components. The tumor cells were stained positively for keratin, S-100 protein, glial fibrillary acidic protein (GFAP) and muscle-specific actin. Distant metastasis in the right jaw developed 8 years after the initial surgery and the metastatic deposit showed a similar morphology and immunoreactivity. Myoepithelial tumors are generally considered as benign or low-grade lesions and distant metastasis has been rarely documented. The present case presents the possibility of delayed occurrence of distant metastasis in myoepithelial tumor of the breast.- - - - - - - - - - ranking = 0.029045425381149keywords = cell (Clic here for more details about this article) |
9/132. 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 = 0.27157512621143keywords = spindle, cell (Clic here for more details about this article) |
10/132. myoepithelioma arising from the buccal gland: histopathological and immunohistochemical studies.A rare case of myoepithelioma of the buccal gland in a 54-year-old Japanese woman is reported. As the swelling exhibited a normal mucosal color and was relatively well defined, showing no ulcers, a benign salivary gland tumor was suspected upon clinical inspection. Microscopically, the parenchyma of the present case mainly consisted of plasmacytoid cells with round nuclei and eosinophilic cytoplasm, and partial spindle cells with eccentric nuclei. The stroma was composed of fibro-hyalinized or myxoid connective tissue that separated from the parenchyma. Immunohistochemically, the cytoplasm of the plasmacytoid and spindle cells was moderately positive for vimentin and GFAP, whereas the buccal gland adjacent to the tumor was negative for these antibodies. S-100 protein reactivity is strong for both types tumor cells. Actin reactivity was negative for both types of tumor cells, notwithstanding the fact that myoepithelial cells of the buccal gland were positively stained. Anti-cytokeratin reactivity was weak for both types of tumor cells in portions of the plexiform and solid areas; nevertheless, the buccal glands were moderately positive. These results suggest that neoplasmic myoepithelial cells exhibit abnormal differentiation and modification. There have been only two published reports of myoepithelioma arising from the buccal gland in the literature to date.- - - - - - - - - - ranking = 1.4858951729583keywords = spindle cell, spindle, cell (Clic here for more details about this article) |
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