Cutaneous deciduosis

Cutaneous deciduosis is an exceedingly rare manifestation of endometriosis potentially mistaken for malignancy and thus far documented solely within s urgical scars. We describe two additional cases, one occurring in a pregnan t 21-year-old woman as a solitary flat erythematous vulvar papule, an extra ordinary location not previously recorded. Histologic examination in that c ase revealed a subepithelial nodular aggregate of atypical large dyscohesiv e cells with accompanying edema and inflammation. An immunohistochemical pa nel showed positivity of the cells For vimentin and Ki-1 (CD30). Intracellu lar sulfated mucin and glycogen were also demonstrated. In a second case, a 27-year-old woman had a nodule at the umbilicus, removed incidentally duri ng the course of cesarean section. Microscopically there were several circu mscribed, multilobulated, intradermal nodules with variably sized lumens fo rmed by crowded large epithelioid cells. The disparate histologic appearanc e of these examples highlights an essential challenge in their diagnosis. C linical recognition is difficult unless suggested by more characteristic hi story or location.