Histopathologic features of genetically determined ovarian cancer.

Inheritance of germline mutations of BRCA1 or BRCA2 genes account for approximately 10% of ovarian carcinomas, but the characterization of these genetically determined cancers is incomplete. The objective of our study was to characterize the histologic features of ovarian carcinomas associated with germline mutations of BRCA1 and BRCA2. Thirty-two ovarian carcinomas associated with germline BRCA1 or BRCA2 mutations and 40 ovarian carcinomas from patients screened as negative for germline mutations were obtained from three centers. A gynecologic pathologist, blinded to mutation status, reviewed each case, with documentation of the histologic type, Gynecologic Oncology Group (GOG) grade, architectural and nuclear grade, Silverberg grade, and mitotic activity. All BRCA1 and BRCA2 mutation-associated cases were invasive serous carcinomas, and of these 50% were GOG grade 3, 41% had an architectural grade of 3 (predominant solid architecture), 84% a nuclear grade of 3, 72% a mitotic score of 3 (>25 mitoses per 10 HPF), and 75% a Silverberg grade of 3. The differences in histologic type (p = 0.001) and Silverberg grade (p = 0.002) between these tumors and the control group were statistically significant and remained so when comparisons between BRCA carriers and noncarriers were restricted to carcinomas of serous histology alone. Ovarian carcinomas associated with germline mutations of BRCA1/BRCA2 are, in this study, invasive serous carcinomas, with a statistically significant higher histologic grade than ovarian carcinomas without BRCA mutations when using the recently proposed Silverberg grading system.