Characteristics and management of male breast parenchymal cysts

Objective: Parenchymal breast cysts are considered to be rare in men and are sparsely described in the literature. The purpose of this study was to review our institution’s experience with male breast cysts in an effort to improve overall understanding and management of this rare entity. Methods: An institutional review board–exempt retrospective study was performed. Radiology reports for males who underwent mammogram and/or breast ultrasound at any of our institution’s primary or satellite locations from January 1995 to January 2020 were screened to find males with breast cysts. If cysts were reported and images were available, case review was performed to confirm parenchymal breast cyst(s) and patient characteristics were collated. Results: Of 5425 male cases presenting for breast imaging, 19 (0.4%) cases of male breast cysts were confirmed, with a mean patient age of 41.6 years (range: 2–81 years). The most common indication leading to cyst discovery was a palpable lump, corresponding to the site of the cyst in 5 (26.3%) patients and near the site where cyst(s) were ultimately discovered in 7 (36.8%) patients. There were 8 (42.1%) instances of cysts without concurrent gynecomastia. Three (15.8%) men underwent needle sampling. There were no cases of atypia or malignancy on needle biopsy or on subsequent clinical follow-up, with median clinical follow-up of 70.3 months (range: 3.3–259.4 months). Conclusion: Male breast parenchymal cysts are rare, but their prevalence is likely underestimated. If detected incidentally or upon targeted evaluation, biopsy may be averted if classic benign cyst features are identified.