Invasive micropapillary carcinoma of the breast in a male patient: Report of a case

INTRODUCTIONWe report a rare case of invasive micropapillary carcinoma in the male breast.PRESENTATION OF CASEA 63-year-old man was referred to our hospital for investigation of a left breast tumor, which could be palpated in the upper lateral quadrant of the left nipple-areola complex. The tumor invaded the areola skin. Ultrasonography showed a 14.8 × 15.0 × 12.4 mm low echoic mass, with an irregular lobulated border. Core needle biopsy indicated invasive ductal carcinoma, but the subtype could not be accurately determined. Mastectomy with axillary lymph node dissection was performed. Pathological examination indicated invasive micropapillary carcinoma, no lymph node metastasis, and a nuclear grade of 2. Immunohistochemical examination showed positive staining for estrogen and progesterone receptors, but negative staining for HER2. The Ki67 index was 5%. Tamoxifen was administered, and recurrence has not been noted for 1 year.DISCUSSIONWomen's IMPC generally shows a high HER2 positivity rate. However, HER2 positivity was noted in only 1 male patient with IMPC (14%) according to our literature review. Furthermore, in all cases of the mixed type that were reviewed, IMPC was associated with papillotubular carcinoma. These findings may be specific to IMPC in male patients.CONCLUSIONIMPC is associated with a high rate of lymph node metastasis or recurrence and advanced vessel invasion, aggressive adjuvant chemotherapy following surgical resection should be selected for patients with IMPC.