Primary clear cell carcinoma of the endometrium: a clinicopathologic study of 20 cases

Primary clear cell adenocarcinoma of the endometrium (CCE) is a rare, aggressive tumor, representing 1-5.5% of all primary endometrial cancers. Twenty cases of CCE were studied, covering the period 1973-1987. Both endometrial curettings and hysterectomy with bilateral salpingo-oophorectomy (BSO) specimens were reviewed. Treatment was total abdominal hysterectomy/BSO for all patients with/without pre- and postoperative and/or post-operative chemotherapy. Grossly the tumors formed fleshy, soft masses and involved most of the endometrial surface. The tumor arose in part in an endometrial polyp in 10 cases. Myometrial penetration was found in 12 cases and varied from 5 to 100%. The neoplasm exhibited the following microscopic patterns in pure form or mixed: papillary, tubulocystic, glandular, and solid. All cases were graded as poorly differentiated (grade 3) adenocarcinomas. The stroma surrounding tumor cells showed a lymphoplasmocytic cellular infiltrate in all cases. Follow-up varied from 5 to 165 months, with a crude survival of 60%; eight patients died; six of those had myometrial invasion of 40-100%. In conclusion, CCEs are specific tumors with defined histologic parameters in which the cytologic grade and/or tumor morphology do not appear to influence outcome. On the other hand, the depth of myometrial invasion and clinical staging are reliable prognostic elements.