Malignant myoepithelioma of minor salivary gland origin.
Myoepithelial cells are a significant component of most types of salivary gland tumors. A small but increasing number of case reports have also shown that true myoepithelioma (ME) forms a distinct clinicopathologic entity of salivary gland tumors with unique histologic features, however, the malignant type of ME is exceedingly rare. The present paper reports a case of malignant ME originating from the palatal minor salivary gland. The patient was a 70-year-old Japanese male with recurrent tumor of the palatal region. Pathologically, the tumor consisted of proliferating polygonal-shaped cells and plump spindle cells with cellular atypia and frequent mitoses, forming lumen-less lobuli or strands. Clear tumor cells were also found in part. The stroma was poorly developed without any myxoid or chondroid features. Immunohistochemical study showed positive stainings for S-100 protein, actin and vimentin in the tumor cells. Ultrastructurally, tumor cells had features of myoepithelial cells.
Takeda
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Department of Oral Pathology, School of Dentistry, Iwate Medical University, Morioka, Japan.
D000199:Actins / Q000032:analysis; D000368:Aged; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009208:Myoepithelioma / Q000473:pathology* / Q000556:secondary / Q000648:ultrastructure; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D009418:S100 Proteins / Q000032:analysis; D012468:Salivary Gland Neoplasms / Q000473:pathology* / Q000648:ultrastructure; D014746:Vimentin / Q000032:analysis
D000199:Actins; D009418:S100 Proteins; D014746:Vimentin