Clear cell carcinoma of the endometrium: an analysis of 21 cases.

Twenty-one cases of clear cell carcinoma of the endometrium are analysed in an effort to characterize the histologic features and biologic behavior of this type of neoplasm in the uterus and thereby to shed further light on the histogenesis of clear cell carcinoma in the female genital tract. The clinical profile of the patients closely paralleled that of women with the usual types of carcinoma of the endometrium. Fifteen (71%) were stage I, five were stage II, and one was stage IV at diagnosis. An assessment of the clinical stage and depth of myometrial invasion are useful in predicting the prognosis. The actuarial survival for all stages is 55.3% at 5 years, which is somewhat lower than that of adenocarcinoma of the endometrium in general. Operation alone or combined with radiation therapy is the treatment of choice for stage 1 clear cell carcinoma of the endometrium. The most cogent evidence for a müllerian rather than a mesonephric origin for clear cell carcinoma in the female genital tract is its presence in the endometrium, a Müllerian derivative. More specific points that support this concept are the findings of clear cell carcinoma confined to an otherwise benign endometrial polyp in two instances, the initimate admixture of clear cell and typical adenocarcinoma in three other instances, and the absence of mesonephric remnants in any of the 21 cases.