['Recruitment of brown adipose tissue is a promising strategy to treat obesity and Type 2 diabetes, but the physiological effects of a large amount of metabolically active brown adipose tissue in humans are unknown.', 'In the present paper, we report a case of massive brown adipose tissue infiltration of the visceral adipose tissue depot in a person with Type 2 diabetes with a catecholamine-secreting paraganglioma. The patient was evaluated with [18F]-fludeoxyglucose positron emission tomography/computed tomography on three occasions: pre-therapy, during α-blockade and postoperatively. During surgery, biopsies of visceral and subcutaneous adipose tissue were obtained and evaluated for brown adipose tissue. At diagnosis, brown adipose tissue glucose uptake, assessed by [18F]-fludeoxyglucose-positron emission tomography, was massively increased. [18F]-fludeoxyglucose uptake was confined to known locations for brown adipose tissue, with additional uptake in the visceral adipose tissue. As a result of increased thermogenesis, resting energy expenditure was doubled. After surgical removal of the tumour, antidiabetic medicine was no longer needed, despite an 8.2-kg weight gain.'] Does chronic adrenergic stimulation induce brown adipose tissue differentiation in visceral adipose tissue?