Hibernoma is a benign tumor of brown fat . In adults, scattered brown fat deposits are most commonly found in the subcutaneous regions of the back, especially between the scapulae, and within the axilla, thorax, and mediastinum. Hibernomas are more frequently found in the interscapular region, but a few cases have been described in other sites such as scalp, parotid region, submental space, larynx, mediastinum, and neck

Microscopically it was a neoplastic lesion with lobular pattern and composed of cells that show varying degrees of differentiation, ranging from uniform, round to ovoid, granular eosinophilic cells with a distinct cellular membrane to multivacuolated cells with multiple small lipid droplets and centrally placed nuclei.