Morphological characteristics of rat peritoneal endometriotic lesions. Lesions after 15 days (A, C) and 30 days (B, D), eutopic endometrium (E) and histogram of implant areas (F). Most of the explants were well vascularized (arrowheads) and cystic (arrows), resembling human peritoneal endometriosis. Compared between groups, there was no detectable difference in the lesion size. Histologically, the endometriotic tissues (C, D) were similar to the eutopic endometrium (E) because they both contained endometrial glands and stromal cells, as revealed by hematoxylin and eosin coloration. Magnification × 200.