Malignant rhabdoid tumors are morphologically characterized by the presence of sheets of large polygonal cells with abundant cytoplasm containing eosinophilic inclusions. They have vesicular nuclei, often with prominent central nucleoli. The term rhabdoid tumor was originally coined to describe a group of rare, aggressive renal neoplasms of childhood. Since then, similar lesions, so-called extrarenal malignant rhabdoid tumors have been increasingly reported. The evidence to date suggests that, at least in extrarenal locations, rhabdoid tumors do not constitute a homogeneous entity, but rather represent the shared morphological pattern of a diverse range of malignant neoplasms. Although such rhabdoid features are not uncommon in metastatic malignant melanoma, they have only once been briefly described in a primary lesion. We report three further cases of cutaneous primary malignant melanoma with rhabdoid morphology.

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In a review of 574 cases of gastric carcinoma, 50 (8·7%) proved to be mucoid using defined microscopic criteria. Three histological types were recognized: pure signet-ring cell carcinoma (three cases); tumour of mixed pattern (41 cases); and an easily recognized, well differentiated type (six cases). This last group pursued an indolent course and had a mean survival time of nine years compared with mean survival times in the other two groups of five and 18 months respectively.

Sertoliform endometrioid adenocarcinomas of the ovary are well recognized but, curiously, a sertoliform pattern has not previously been noted in endometrioid adenocarcinomas of the endometrium. An endometrial tumour is described which showed in some areas the typical appearances of an endometrioid adenocarcinorna and in others a pattern closely resembling that of a Sertoli cell tumour.