Fibroepithelioma-like changes associated with anogenital epidermotropic mucinous carcinoma. Fibroepitheliomatous Paget phenomenon.

We describe two patients with crusted perineal plaques that were biopsied and diagnosed as Paget's disease. Resection specimens of each contained a dermal mucinous carcinoma with extensive epidermotropism and coexistent epidermal basaloid proliferations closely resembling fibroepithelioma (Pinkus). The presence of the Paget phenomenon was supported by histochemical, immunohistochemical, and ultrastructural evidence. No other primary neoplasms were found in either patient. Followup at 2 1/2 and 3 1/2 years, respectively, has been negative. We conclude that either the fibroepitheliomatous changes may be induced by or may represent a collison (unlikely) with the epidermotropic mucinous carcinoma. It is proposed that the concept fibroepitheliomatous Paget phenomenon be used to stand for the histologic changes common to our cases as well as those previously reported.