Tomoyuki Ohuchi

Basaloid-squamous cell carcinoma of the oral mucosa: Report of two cases and study of the proliferative activity

Two cases of basalold‐squamous cell carcinoma (BSC) of the oral mucosa are described. The first case occurred at the floor of the mouth in a 58‐year‐old man, and the second case occurred at the mandibular gingiva in a 79‐year‐old woman. The laboratory data of the first case showed a positive response to hepatitis C virus antibody. in the first case, the tumor mass measured 4 times 4 cm in size, and was i‐texl at the lingual side of the median mandible beside the sublingual gland. In the second case, the tumor mass measured 25 times 15 mm In size, and was located in the alveolar mucosa of the right mandible. Histologically, both tumors showed a neoplastic epithelium arranged in a solid pattern with evidence of peripheral palisading, central necrosis, and some squamous differentiation. The pro‐ilferathfe activities of the BSC were compared with conventional squamous cell carcinomas (SCC) in the oral floor and gingiva, respectively, by employing a sensitive argy‐rophillc nuclear organizer region (AgNOR) staining method. The number of AgNOR per nucleus of the BSC was higher than that of any other SCC cases. The results support the opinion that BSC of the oral mucosa has a worse prognosis than conventional SCC.

Malignant myoepithelioma of the oral palate: Ultrastructural and immunohistochemical studies and survey of the literature

Malignant myoepithelioma arising in the palatal gland is extremely rare. The present study demonstrated ultrastructural and immunohistochemical features of malignant myoepithelioma transformed from long-standing benign myoepithelioma occurring in the palatal gland. Microscopically, the tumor mass was composed of plasmacytoid cells and epitheloid cells. The malignant feature was seen only at the area adjacent to the bone. Immunohistochemically, most of the cells were S-100 positive, whereas vimentin and keratin were only partially positive. Glial fibrillary acid protein (GFAP) was positive at the peripheral cells of the solid nests and epitheloid cells with myxoid stroma. Ultrastructurally, filament-rich cells, tonofilament-rich cells, and filament-poor cells were observed. At the area adjacent to the bone, the cells implying malignancy were filament-poor cells in which the luminal structures could be detected. From these findings, a scarcity of filaments in myoepitheliomatous components may imply a malignancy.

Metastasis from a mixed tumour of the salivary gland

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