Image Description
Endometriosis of the urinary bladder. Inactive appearing endometriotic glands are surrounded by scant stroma. Given their location within the bundles of muscularis propria, infiltrating adenocarcinoma must be excluded. The presence of endometrial stroma around the glands, the lack of cytologic atypia or mitotic activity, and the presence of old hemorrhage (siderophages) favor endometriosis.