Abstract
The patient was a 60-year-old man who developed a lump in the left breast in 2003. He visited our clinic in March 2007 due to the gradual enlargement of the lump. Physical findings on examination included a well-defined, smooth, near-spherical tumor (diameter, 4cm) that was palpable around the left areolar region. The axillary lymph nodes were not palpable. Needle biopsy indicated a class III papillary lesion that was diagnosed as a possible case of intraductal papilloma. A left mastectomy was performed in April 2007. Histopathological examination showed that the proliferative cells were negative for CK5/6, p63, CD10, CK14, and SMA. In addition, the cells were negative for SYN, CGA, and CD56, while diffuse positive staining was observed for ER and positive nuclear staining was sporadically observed for S-100P in very few cells. Cells positive for 34βE12 were observed in a mosaic-like pattern within the tumor, while an increased proliferative activity was observed on MIB1 staining. Based on these findings, the patient was diagnosed with non-invasive, ductal carcinoma of male breast. Male breast cancer is a rare condition, particularly in its non-invasive form. We report the present case with reference to literature.
