Androgen receptor expression in vascular neoplasms of the breast.

Introduction: Androgen receptors (AR) have been reported to be present in normal breast tissue and breast carcinomas. The following study was undertaken to assess the expression of AR in vascular neoplasms of the breast.

Materials and methods: All patients with histologically diagnosed hemangioma, angiolipoma, atypical vascular proliferation, and angiosarcoma of the breast were retrieved from the clinical and pathology database at Rush University Medical Center. The slides stained with hematoxylin and eosin were reviewed and immunohistochemical staining for AR (Dako; clone AR441) was performed on paraffin-embedded tissue. Any amount of nuclear staining was considered positive and the intensity of staining was graded as 1+ to 3+. An estimate of the percentage of tumor and stromal cells staining was made.

Results: There were a total of 36 cases, 10 hemangiomas, 20 angiolipomas, 2 atypical vascular proliferation, and 4 angiosarcomas. The male to female ratio was 1:4.1. The average age at presentation for men was 45 years and for women was 56.9 years. Anti-AR expression was present in stromal and adipocyte nuclei of the angiolipomas and stromal cells of hemangiomas and angiosarcomas. Interestingly, normal duct epithelium of the breast was positive in 7 of the 29 women and none in men. Androgen expression was present in 62.5% of the hemangiomas, 55% of the angiolipomas, and 50% of the angiosarcomas. The majority of tumors showed a low-intensity nuclear expression of androgens, with 1+ intensity in 13 cases and 2+ intensity seen in 2 cases, and only 1 case of angiolipoma showed 3+ expression. All positive cases of angiolipoma (55%) showed AR in adipocytes and stromal cells.

Conclusions: Vascular neoplasms are uncommon tumors in breast and majority of them are benign. Androgen expression is present in >50% of benign vascular neoplasms. Stromal cells and adipocytes typically express AR only in angiolipomas, suggesting a role of androgens in pathogenesis and growth of this neoplasm.