Coincidence of Granulosa‐Cell Tumour of Ovary and Development of Carcinoma in Rectal Endometriosis

A case is reported of the co‐existence of granulosa‐cell tumour in the ovary and endometrial cancer of the rectum in a 36‐year‐old woman. The endometrial cancer originated in the endometriotic tissue of the muscular layer of the rectum. Ovarian and pelvic endometriosis together with endometriosis of the small intestine had been diagnosed earlier. The patient had presented symptoms of endometriosis for several years. The simultaneous occurrence of granulosa‐cell tumour and malignant transformation of endometriotic tissue is considered by the authors as probably having a causal background, analogous to the development of hyperplasia of uterine endometrium or carcinoma of the endometrium in patients with hormone producing granulosa‐cell tumours.