Morphometric analysis of endometrial adenocarcinoma: 1. Does architectural dedifferentiation accompany deep invasion by endometrial adenocarcinoma?

Important prognostic factors for endometrial adenocarcinoma include histologic differentiation, depth of myometrial invasion, and clinical stage. Deep myometrial penetration is more commonly observed with poorly differentiated carcinomas, but it is unknown if these tumors are poorly differentiated de novo, or if selection toward more aggressive, less differentiated cells occurs during invasion. To study this question, we performed a morphometric analysis to quantitate the amount of glandular differentiation in superficial portions of 22 endometrial carcinomas for comparison with deep portions of the same neoplasm. Point counting of randomly selected fields was performed on histologic sections of hysterectomy specimens of 22 women with stage I endometrial adenocarcinoma. The components enumerated were tumor cells participating in gland formation (DI), non-gland-forming tumor cells (UI), tumor gland lumens (LUM), inflammatory cells (IC), and stroma (endometrium or myometrium) (ST). Slides of tumors were divided into superficial, middle, and deep thirds. No statistically significant differences were seen between superficial and deep thirds (UI: 45% vs. 43%; DI: 33% vs. 32%; LUM: 22% vs. 24%; IC: 3% vs. 3% of points counted, p greater than .1, paired t-test). The density of tumor cells relative to stroma was greater in the superficial region (55% vs. 41%, p less than .001, paired t-test). Additionally, field-to-field heterogeneity was examined by four methods. No relationship between increased heterogeneity and poor prognosis was identified. These findings do not support the concept that invasion by endometrial adenocarcinoma is accompanied by architectural dedifferentiation.