Occurrence of endometrial glandular dysplasia precedes uterine papillary serous carcinoma

Endometrial glandular dysplasia (EmGD) is a newly defined entity that is commonly and specifically associated with serous endometrial intraepithelial carcinoma and uterine papillary serous carcinoma (UPSC). Endometrial glandular dysplasia has been proposed as a true precancerous lesion of UPSC based on our recent studies showing morphological and molecular linkages between these 2 lesions. The present report is to examine if EmGD occurs before UPSC development and to define the period from the occurrence of EmGD to a full-blown UPSC by studying their clinicopathologic features in a retrospective setting. A total of 250 UPSC and 258 benign cases were used as initial study source. To identify if EmGD existed before the development of UPSC, we blindly reviewed all available endometrial biopsies from a period of 3 months or earlier before hysterectomies. These included an available pool of 27 biopsy specimens from UPSC group and 29 samples from benign control group. Any endometrial abnormalities, which morphologically qualified as EmGD as defined previously in preceding biopsies were recorded. Among all endometrial biopsies before hysterectomies, we morphologically identified a total of 10 EmGD cases; 9 (33%) of 27 were from UPSC group and 1 (3.5%) of 29 were from benign control group. All 10 morphologically diagnosed EmGD cases showed a high p53 staining score (≥5) except 1 noncontributory from UPSC group and 1 from the benign control group with a score of 0. A high MIB-1 index score was seen in all EmGD cases, whereas low index was found in morphologically benign biopsies. The main purpose of this study is to report these retrospectively identified EmGD cases. The period from identifying EmGD to the presence of either a serous endometrial intraepithelial carcinoma or a full-blown UPSC ranged from 16 to 98 months with an average of 33 months. We conclude that occurrence of EmGD precedes the development of UPSC. The findings support our recently proposed UPSC development model, in which EmGD is likely to be a precursor lesion of UPSC. Further studies are needed to address issues in regard to molecular and cellular mechanisms, reversibility, risk of UPSC development, and clinical management of EmGD.