SIGNIFICANCE OF PAPILLARY (VILLOGLANDULAR) DIFFERENTIATION IN ENDOMETRIOID CARCINOMA OF THE UTERUS

The frequency, topography, and significance of papillary (villoglandul ar) differentiation were examined in 142 cases of endometrioid (typica l) carcinoma of the endometrium. Forty-four (31%) of the 142 cases sho wed papillary differentiation, including eight carcinomas limited to t he endometrium and 36 cases with myometrial invasion. In 24 (67%) of t he 36 cases with myometrial invasion, papillary differentiation was fo und in both the endometrial component of the carcinoma and in tumor in vading the myometrium. In the remaining 12 cases, papillary differenti ation was found in the endometrial component but not in tumor invading the myometrium, which showed either glandular or solid growth pattern s. When patients were divided into two groups based on the presence or absence of papillary differentiation, regardless of its location, the two groups did not differ in prognosis or frequency of pathologic cha nges associated with outcome. In the subgroup of patients with tumors showing myometrial invasion, however, endometrioid carcinomas displayi ng papillary differentiation in the myometrium were associated with a higher frequency of vascular invasion (p = 0.007), a higher rate of ly mph node metastasis (p = 0.001), and worse outcome (p = 0.05) compared with carcinomas showing myometrial invasion in the form of glandular or solid patterns regardless of the presence or absence of papillary d ifferentiation in the endometrium. The results of the present study su ggest that papillary differentiation is of significance in endometrioi d carcinoma. If these findings can be confirmed, a separate designatio n for these tumors as ''papillary endometrioid carcinomas'' or ''villo glandular endometrial carcinomas'' would be helpful if use of these te rms was limited to endometrioid carcinomas manifesting papillary diffe rentiation in the myometrium.