Mesonephric (clear cell) endometrial cancer

Clear Cell Endometrial Cancer is a rare nonendometrioid endometrial carcinoma detected in 1–6 %. The aim of the study was to determine clinical and morphologic features of Clear Cell Endometrial Cancer. Materials: All the cases with Clear Cell Endometrial Cancer treated in the N. N. Petrov Research Institute of Oncology (Saint-Petersburg) were identified from surgical pathology files from 1985 to 2010 years. Saint-Petersburg Population Cancer Registry data (2000–2005 years period) and N. N. Petrov Research Institute of Oncology Hospital Cancer Registry data (1985–2010 years period) were analyzed. The population based study included 3 224 cases of endometrial cancer patients, the hospital study — 3 345 patients. Results: A review of 3 345 cases of endometrial cancer revealed 73 cases (2.2 %) of Clear Cell Endometrial Cancer. Clear Cell Endometrial Cancer registered in elder women with late menopause and atrophic endometrium. The tumor is a highly malignant variant of endometrial carcinoma with deep myometrial invasion (42.5 %), high rate of metastasis (39.1 %) even in cases with superficial invasion (23.0 %) versus endometrioid endometrial cancer: 6.0 %, 14.2 % and 9.0 % respectively. Clear Cell Endometrial Cancer has a poor prognosis with 3-year observed survival 62.7 %, 5-year observed survival — 52.2 % (Saint-Petersburg Population Cancer Registry), 70.9 % (3-year survival) and 61.8 % (5-year survival) according to the N. N. Petrov Research Institute of Oncology Hospital Cancer Registry data. Whereas prognosis in patients with endometrioid endometrial carcinoma is much more favorable: 3-year observed survival 79.4 %, 5-year observed survival — 75.5 %