Invasive carcinomas of the male breast: a morphologic study of the distribution of histologic subtypes and metastatic patterns in 778 cases

Abstract

The current investigation was conducted to evaluate the proportional distribution of the various histologic subtypes (including newly recognized variants) of male breast carcinomas, to determine whether any histologic subtypes occur with a frequency that is markedly discordant with the expected frequencies from published data on parallel female breast tumors. We also aimed to document the distribution of malignancies metastatic to the breast. Seven hundred fifty-nine archived cases of primary invasive carcinoma involving the male breast were retrieved and sub-categorized into histologic subtypes according to contemporary criteria. Six hundred forty-three (84.7%) tumors were pure infiltrating ductal carcinoma (IDC) not otherwise specified. The most common of the remainder included papillary carcinoma with invasion in the form of IDC (n = 34), mixed IDC and mucinous carcinoma (n = 26), and pure mucinous carcinoma (n = 21). In 19 cases, metastases from other sites involved the breast, most commonly (58%) cutaneous melanoma. Invasive carcinoma of the male breast appears to display a morphologic spectrum and distribution of histologic subtypes that is comparable to those of the female breast, with some expected variation. Compared with published experience on their female counterparts, there is a two-fold increase in the frequency of invasive papillary carcinoma in the male breast. Finally, the most common tumor metastatic to the male breast in this series was cutaneous melanoma.

Fig. 1

Representative pathologic images of the various histologic subtypes. a and b Gross and microscopic images of infiltrating duct carcinoma, the most frequently encountered histologic subtype (b original magnification ×160). c A colloid (mucinous) carcinoma (right field) occurring in a gynecomastoid breast (left field) (original magnification ×100). d The single case of a secretory carcinoma was in a 9-year-old boy, the youngest patient in this series (original magnification ×140). e and f Examples of papillary intraductal carcinoma with invasion in the form of infiltrating duct carcinoma [original magnifications: ×100 (e), ×120 (f)]