Pathology of endometriosis.

In summary, endometriosis is a protean pathologic entity of uncertain nature and etiology, occurring commonly in the pelvis and rarely in remote sites. The lesions are characterized by gross and microscopic evidence of endometrium, past and present hemorrhage, inflammatory response, scarring, and dense adhesions. Electron microscopic evaluation suggests that early lesions are more common than appreciated, often retroperitoneal, and not clinically recognized. The diagnosis is established by the identification of microscopic foci of endometrium, although often the end stage reveals only hemosiderin-laden macrophages, foreign body giant cells, and proliferation of fibrous connective tissue. The presence of endometriosis alters the biology of the pelvic peritoneum in ways not universally agreed upon, but which undoubtedly influence the clinical manifestation of the disease.