Toward understanding the natural history of ovarian carcinoma development: a clinicopathological approach

The natural history of the development of ovarian carcinoma is not known. It also remains undetermined whether ovarian carcinomas develop from benign and/or borderline malignant tumors or arise de novo from the ovarian surface epithelium.

To address these issues clinicopathologically, we reviewed the clinical charts of 543 patients with epithelial ovarian carcinoma and 252 patients with borderline tumors who underwent laparotomy at seven hospitals and collected patients whose clinical and transvaginal ultrasonography (USG) findings for adnexal regions 12 months or fewer prior to the surgery were available. Histological slides of the resected specimens were reexamined concerning the diagnosis and histological grade, as well as the presence or absence of benign- or borderline-like lesions adjacent to the carcinoma.

Forty-nine patients had had gynecological examination with transvaginal USG 12 months or fewer prior to laparotomy. Among them, 35 had carcinomas (11 serous, 6 mucinous, 8 clear cell, 10 endometrioid) and 14 had borderline tumors (8 serous, 6 mucinous). Of the 35 patients with carcinoma, 19 (54%) had been followed up for benign-appearing cysts or endometriotic cysts. In these cases, serial USG examinations revealed an increase in size and/or appearance of the solid part of the cyst. In the remaining 16 (46%), however, there had been no apparent abnormalities in USG, and such cases occurred most frequently for serous carcinomas.

Our findings suggest that approximately half of ovarian carcinomas develop secondarily from preexisting, benign-appearing cysts or endometriotic cysts, whereas the remaining half seem to develop suddenly from a normal-appearing ovary. This appears to be consistent with two possible pathways of ovarian carcinoma development; adenoma-carcinoma sequence and de novo carcinogenesis.