Recurrent Male Breast Cysts in the Absence of Gynecomastia: A Rare Case Report

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Abstract Publications focusing on male breast neoplasms are underrepresented in literature as most lesions are benign and less prevalent than their female counterparts. Only one case of benign male breast cyst without gynecomastia has been reported in English literature thus far, although without recurrence. We highlight the case of a 73-year-old male with history of remote non-Hodgkin lymphoma and prostate carcinoma who underwent an ultrasound-guided fine-needle aspiration (US-FNA) of a palpable 4-cm soft, nontender, mobile, left subareolar breast mass. He had no nipple discharge, skin changes, or family history of breast carcinoma. Ultrasound revealed an anechoic mass devoid of blood flow and no lymphadenopathy. US-FNA yielded 13 mL of colorless fluid and no residual lesion was visualized on postprocedural ultrasound. Microscopically, the smears were acellular and the filter preparation demonstrated crystalline debris with rare fragments of epithelial tissue, favoring the diagnosis of cyst fluid with degenerated cyst lining. Due to the lack of lobular units and a less developed ductal system compared to females, cysts are highly unusual in the male breast, and thus close follow-up was recommended. The patient returned 10 months later with a recurrent 4-cm fluctuant mass in the same location. Two adjacent anechoic cysts with a submillimeter mural projection were seen on ultrasound and targeted during US-FNA. Both cysts disappeared after drainage of 13 mL of colorless fluid. Again, cytology showed a predominantly acellular collection with scant morphologically similar epithelial fragments. All breast masses in men warrant evaluation, especially in patients with a history of malignancy. Although rare, benign male breast cysts without associated gynecomastia do occur. The lesions are amenable to both diagnosis and treatment by FNA, allowing for a less invasive procedure, without undermining patient care.