Malignancy arising in extragonadal endometriosis: a case report and summary of the world literature.

A case of clear cell carcinoma arising in endometriosis of the retroperitoneum is presented. It occurred 5 years after supracervical hysterectomy and bilateral salpingo-oophorectomy and following 4 years of estrogen therapy. The literature concerning malignancy developing in extragonadal endometriosis has been reviewed and is summarized as follows: 1) 45 cases have been compiled, of which 32 were carcinomas and 13 sarcomas; 2) adenocarcinoma was the most common histologic type, although virtually every tumor of müllerian derivation has been described; 3) the typical patient was nulliparous and perimenopausal; 4) the rectovaginal septum was the most common site, and in general the frequency of malignancy in a given site parallels the frequency of endometriosis in that location; 5) simultaneous tumors of the uterus or ovary were present in seven cases (15%); 6) prognosis appeared affected by site and histologic type; 7) a history of prior pelvic irradiation to effect castration was present in three (9%) of the patients with adenocarcinoma; and 8) four (12%) of the patients with adenocarcinoma were subjected to exogenous estrogens or estrogen-secreting ovarian tumors.