Endomyometriosis arising in the uterosacral ligament: a case report including a literature review and immunohistochemical analysis.

We report a case of endomyometriosis arising in the left uterosacral ligament of a 29-year-old woman. The central cavity of the uterine-like mass was lined by pseudo-stratified columnar epithelium and endometrial stroma. The wall of the cyst consisted of bundles of smooth muscle cells. Immunohistochemical analysis demonstrated both alpha-estrogen receptor and progesterone receptor immunoreactivities in the epithelial, stromal and smooth muscle cells. A relatively high proliferating activity was also demonstrated in these cells by Ki-67 immunostaining. These findings suggest that the mass was hormone dependent and had a relatively rapid evolution.