Abstract
BACKGROUND: Ductal carcinoma in situ of the male breast is an unusual lesion and most often associated with invasive carcinoma. On rare occasions when the in situ component is present in pure form, histological grade is almost always low to intermediate. Imaging for these patients is difficult as gynecomastia is often present and can mask underlying calcifications or carcinoma. CASE REPORT: We report a case of pure high-grade ductal carcinoma in situ of the male breast in a patient with clear nipple discharge. Breast mammography showed bilateral gynecomastia and benign calcifications. Subsequent breast ultrasound showed dilated ducts of the left breast, and a left breast ductogram showed filling defects suggestive of a papilloma. Excisional biopsy and subsequent mastectomy were consistent with high-grade ductal carcinoma in situ. CONCLUSION: Male breast cancer is uncommon and, although there is increasing awareness, it is less studied compared to female breast cancer. With a clinical history of nipple discharge of any kind, further evaluation with imaging should be considered. In males with gynecomastia, it is important to remember that ductal carcinoma in situ, even of high grade, is difficult to detect on mammography and may not be associated with suspicious calcifications.