Case report: hibernoma, a rare male breast mass

• Published in: Journal of surgical case reports Vol. 2025; no. 1; p. rjae820
• Main Authors: Sajdlowska, Joanna, Fawole, Funmilayo, Patel, Anjeli, Radwan, Nawras, Yang, James, Christian, Derick
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.01.2025
• Subjects: Body fat; Case Report; Case reports; Ultrasonic imaging; breast mass; brown fat tumor; male breast mass; hibernoma
• ISSN: 2042-8812; 2042-8812
• DOI: 10.1093/jscr/rjae820

Hibernomas are rare, benign neoplasms characterized by the presence of brown adipose tissue. Although these tumors may arise in any region of brown fat, they predominantly occur in the thigh, shoulder, back, and neck. Hibernomas are rarely found in mammary tissue, with a higher prevalence in females than males. This case report highlights a unique presentation of a 20 cm hibernoma mass found in the right breast of a 31-year-old male. A diagnostic bilateral mammogram, unilateral MRI, and ultrasound were used to evaluate the mass. The patient underwent an intra-operative ultrasound-guided needle biopsy and left total mastectomy, revealing the diagnosis of hibernoma with fat necrosis. This report aims to delineate the pathological, diagnostic, and clinical features associated with breast hibernomas and to offer a comprehensive review of the literature on the subject. This case report also serves to expand the differential for breast mass in male patients, with a focused aim to prevent delayed diagnosis and treatment.