Peritoneal leiomyomatosis disseminata is an exceptional benign disease with characteristic multifocal subperitoneal smooth muscle cell growth. We report and exceptional case associating pelvic endometriosis and mimicking cancer of the ovary. Surgery was performed and was found a posteriori to be excessive in light of the good prognosis of this disease. Positive hormone receptor assays on the surgical specimen favoured ovarian steroid hormone involvement in the aetiopathology of this strange disease.