[Endometrial metastasis of a "balloon" cell melanoma mimicking a "xanthomatous endometritis"].

Xanthomatous changes are unusual lesions of the corpus endometrium that may mask endometrial carcinoma. The term "xanthomatous endometritis" refers to morphological changes frequently induced by estrogen stimulation. We report for the first time a case of uterine metastasis of balloon-cell melanoma mimicking xanthomatous endometritis. Light microscopic, immunohistological, and ultrastructural results are presented and discussed in connection with our ideas on the pathogenesis of this peculiar tumor. The findings favor the hypothesis of a regressive phenomenon in the balloon-cell transformation of melanoma cells. The melan-A immunohistology seems to be more important in the diagnosis of balloon cell melanoma than the classic melanoma antibody HMB 45.