A SERIAL SECTION STUDY OF VISUALLY NORMAL POSTERIOR PELVIC PERITONEUMFROM BABOONS (PAPIO-CYNOCEPHALUS, PAPIO-ANUBIS) WITH AND WITHOUT SPONTANEOUS MINIMAL ENDOMETRIOSIS

Objectives: To determine if microscopic endometriosis exists in visual ly normal pelvic peritoneum from baboons with and without endometriosi s. Design: Observational histologic study at Institute of Primate Rese arch, Nairobi, Kenya. Subjects: Seventeen baboons including 13 adult f emales (5 with histologically proven endometriosis, 8 with a normal pe lvis) and 4 juveniles (1 female and 3 males). Interventions: Diagnosti c laparoscopy with identification of visually normal pelvic peritoneum before euthanasia, followed by laparotomy with excision of a large ar ea (at least 4 x 6 cm or 24 cm(2) per animal, 408 cm(2) surface in all baboons) of this visually normal-appearing peritoneum. Main Outcome M easure: Presence of microscopic endometriosis (endometrial glands and stroma) in serial sections of visually normal pelvic peritoneum. Resul ts: Two adjacent glandular structures compatible with endometriosis we re found in normal peritoneum obtained during menses from one female b aboon without macroscopic disease. Microscopic endometriosis was not d etected in the other female primates with or without macroscopic disea se or in male animals. Conclusion: Microscopic endometriosis was found in only 1 of 14 female baboons (prevalence 7%; 95% confidence interva l 0% to 33%) with visually normal pelvic peritoneum. These findings su ggest that, with the paucity of human data available, more studies are needed before concluding that massive microscopic disease exists in v isually normal-appearing peritoneum of women.