Malignant nodular hidradenoma.

A 54-year-old male farmer was seen in May 1990 with a violaceous, exulcerated tumor, 2x1.5 cm in diameter, localized to the sternal area of the chest. The tumor had been present for 30 years, showing slow progressive growth; it was excised, but recurred 2 years before our initial evaluation. The tumor was again excised with a wide free margin. The histopathologic study showed an ill-defined, epithelial neoformation, formed by lobules of clear polygonal cells at the deep dermis and subcutaneous tissue; there was a second group of smaller cells with a basaloid aspect, a few of them presenting slight atypia. The tumoral lobules were surrounded by a myxoid material with vascular proliferation. The epidermis was normal. The histopathologic report was of a malignant nodular hidradenoma. No evidence of lymph node or distant metastases was found. One year after the excision, the tumor recurred at the surgical site, and an axillary lymph node showed metastatic cells. The lesion was excised for a third time and the patient was lost to follow-up.