Hibernoma presenting as an asymptomatic neck mass

An unusual presentation of a rare benign tumor in the head and neck: A review of hibernomas

“…Tumors composed of brown adipose tissue were first described by Merkel in 1906, and later termed “hibernomas” by Gery in 1914 . Hibernomas typically occur in the third or fourth decade of life as mobile, nontender, asymptomatic masses, with a slight female preponderance . Patients typically present when the hibernoma becomes large enough to compress surrounding structures.…”

“…A hibernoma is a rare, benign, lipid‐containing tumor, consisting of brown adipocytes similar to the brown fat seen in hibernating animals . Approximately 100 cases of hibernomas have been reported, with approximately 10 cases in the head and neck region . A hibernoma typically presents as a nontender, lobulated mass with benign growth pattern .…”

“…1 Approximately 100 cases of hibernomas have been reported, with approximately 10 cases in the head and neck region. 2 A hibernoma typically presents as a nontender, lobulated mass with benign growth pattern. 1 In this case report we present a left neck hibernoma, likely arising from the scalene muscles with focal muscle infiltration.…”

Hibernoma larynx with large multinodular goitre: unusual airway challenge

“…Hibernomas appear in regions of fetal brown fat deposits such as on the back, thorax, axilla and retroperitoneum; however, they have also been reported in regions devoid of brown fat such as popliteal fosse and thigh 3. There are two theories linked to the origin of hibernomas, the first suggests remnants of brown fat dispersed in the body from where they grow, the other suggests a transformation of white fat into brown fat and its neoplastic growth 4.…”

“…Hibernomas present only when large enough to disturb the surrounding anatomy 6 7. Clinically, they are firm, slowly growing, non-tender masses 3. MRI is the imaging modality of choice; it shows a heterogeneous enhancing mass with focal areas of hypointensity and internal septations.…”