Malignant transformation of vaginal endometriosis.

A well-documented case of extraovarian endometriosis undergoing malignant transformation is presented. A vaginal focus of endometriosis was biopsied over a 13-year interval during which time progression from benign to malignant disease was observed. Exogenous estrogen replacement was administered throughout the interval of transformation. The pathology, pertinent literature, and implications of the present case are discussed.