Invasive Lobular Carcinoma of the Male Breast With BRCA2 Mutation.

Male breast cancer (MBC) is a rare condition, accounting for < 1% of all breast cancer cases. Reports of bilateral synchronous MBC are even more uncommon. Although lobular carcinoma is generally absent in the male mammary gland, a few cases of lobular carcinoma in MBC have been documented, comprising 1%-2% of all MBC cases. A man in his 80s presented to our hospital with a mass on his left nipple. After detailed examination, he was diagnosed with invasive ductal carcinoma of the left breast and invasive lobular carcinoma of the right breast. Because he had a family history of breast cancer, he underwent genetic testing and was found to have a BRCA2 gene mutation (c.331_347delinsC [p.Asn111Leufs∗5]). Simultaneous surgery was performed for bilateral breast cancer. Although drug therapy and radiation therapy were recommended after the operation, the patient was under observation due to his advanced age. A brief literature review is presented in this section.