Large Unilateral Adrenal Mass with Surrounding Brown Fat: A Case Report.

Pheochromocytomas are rare tumors derived from chromaffin cells located in the adrenal and extra adrenal tissues. Pheochromocytomas are diagnosed biochemically and localized using different imaging modalities. The definitive management is surgical resection. Brown adipose tissues are normally present during fetal development, with regression over time. Brown adipose tissues are thermogenic and usually located in the neck, mediastinum, and retroperitoneum. Here, we report a case of a unilateral pheochromocytoma surrounded by brown fat. The abnormal stimulation of brown fat noted on positive emission tomography scan (PET) resolved after the pheochromocytoma was resected.