Race-Related Differences in the Clinical Presentation and Histopathologic Features of Phyllodes Tumor.

Background: Phyllodes tumor (PT) is a rare fibroepithelial lesion of the breast with variable malignant potential. Black women have a higher incidence of a related benign tumor, fibroadenoma, but there are limited epidemiological data on PT. The aim of our study was to evaluate race-related differences in the clinicopathologic features and outcomes of PT.

Methods: Our institutional pathology database was queried for breast specimen reports from 01/2009 to 10/2019 to identify patients with a pathologic diagnosis of PT. Chart review and detailed slide review were performed to obtain clinical and histopathologic variables, respectively.

Results: Among twelve patients, two had malignant PT, three had borderline PT, and seven had benign PT. All patients with malignant and borderline PT were black, compared with 29% of those with benign PT. There were no apparent race-related differences in specific histopathologic features among black vs. non-black women with benign PT. Malignant and borderline PT were relatively larger than benign PT, with mean tumor sizes of 9.0 cm (standard deviation [SD] 4.7 cm), 12.2 cm (SD 9.4 cm), and 5.4 cm (SD 5.8 cm), respectively. Two women had a local recurrence, both of whom were black.

Discussion: In this single-institution retrospective study, we observed disproportionate rates of aggressive histopathologic features and disparate outcomes among black women with PT. A multi-institutional PT registry would facilitate improved knowledge about race-related differences in the presentation and outcomes of this rare tumor.