Intense FDG Activity in the Brown Adipose Tissue in Omental and Mesenteric Regions in a Patient With Malignant Pheochromocytoma

A 39-year-old man who had a history of surgical excision of left adrenal pheochromocytoma 3 years ago underwent an FDG PET/CT scan to evaluate possible metastatic/recurrent disease. In addition to multiple FDG-avid lesions typical of hypermetabolic malignant disease and the FDG uptake in regions rich in brown adipose tissue, there was also intense FDG activity in the omental and mesenteric regions, which are not common locations of elevated FDG activity. On the repeat FDG PET/CT scan 3 days later after the patient was prepared with propranolol, the omental and mesenteric FDG activity was diminished.