Endometriosis involving the ileocaecal junction with regional lymph node involvement in the baboon--striking pathological finding identical between the human and the baboon: a case report.

The baboon is an established model for endometriosis research. This report describes the occurrence of spontaneous endometriosis involving the ileocaecal junction and associated regional lymph nodes in the baboon. All endometriotic foci lacked the nuclear atypia, abnormal mitotic activity and altered nuclear-to-cytoplasmic ratio typical of malignancy. These findings are identical to reports in the human in which ileocaecal and colonic endometriosis is associated with endometriosis in pericolonic and mesenteric lymph nodes. The similarity between baboon and human colonic endometriosis in both location and pathology is striking and lends further evidence supporting the validity of the baboon as a model for human endometriosis.