Bilateral and synchronous male breast cancer: a case report.

Genetic mutational characterization of synchronous bilateral male breast cancer (BC) has been poorly reported due to its rarity. Herein, we present a 55-year-old male patient who was diagnosed with bilateral breast cancer (BBC) and harbored different gene mutations. The diagnosis of synchronous bilateral breast cancer (SBBC) was made using ultrasonography, magnetic resonance imaging (MRI), mammography and core-needle biopsy. Subsequently, bilateral modified radical mastectomies were performed, and histopathologic examination revealed invasive ductal carcinoma. To further investigate the genetic profile of the patient, the biopsy tissue from both breasts and a blood sample were subjected to targeted next generation sequencing (NGS). The genomic profile of the left breast (LB) sample revealed two copy number variations (CNVs), amplification of MCL1 and DAXX, while the right breast (RB) sample showed no obvious mutation. We are reporting this case along with its clinicopathologic findings and genetic investigations, since SBBS occurs extremely rarely, especially in men. The heterogeneity in gene mutations observed in this case may suggest a different pathogenesis and the need for different therapy strategies.