Giant hibernoma of the thoracic pleura and chest wall

Abstract

Hibernoma is a rare tumor containing prominent brown adipocytes that resemble normal brown fat. Brown fat (versus white fat) is predominantly found in hibernating mammals and infants. Brown fat adipocytes contain a higher number of small lipid droplets and a much denser concentration of mitochondria. The tumor can occur in a variety of locations however the extremities, followed by the head and neck, have been the most common sights. All variants of hibernoma described have followed a benign course with the majority presenting as a small, lobulated, nontender lesions. We present a case of a giant hibernoma arising from the pleura which invaded the intra and extra-thoracic chest.

Keywords: Hibernoma; Lipoma; Thoracic wall; Pleural neoplasm; Thoracic neoplasms

Core tip: Hibernomas are rare tumors containing brown fat. They are uncommonly located on the chest or pleura. Differentiation for other malignant tumors requires histologic evaluation. Surgical excision is the treatment of choice. Treatment of large and symptomatic hibernomas is surgical excision. This is curative in the majority of patients with the exception of a rare case reported having recurrence after unclear resection margins.