Fluorine-18-FDG PET/CT in a patient with angiomyolipoma: Response to mammalian target of rapamycin inhibitor therapy.

We report on a 27 years old female patient who was referred to our department for whole-body as well as dynamic positron emission tomography/computed tomography (dPET/CT) scan of the upper and middle abdomen with fluorine-18-fluorodeoxy glucose (F-FDG), for further evaluation of a mass in the left adrenal gland region. Positron emission tomography showed a suspicious, enlarged, hypermetabolic mass with an average standardized uptake value (SUV) of 4.5 and a maximum SUV of 5.9. The patient was referred for biopsy, which revealed an angiomyolipoma, a perivascular epithelioid cell tumor (PEComa) of the adrenal gland. Perivascular epithelioid cell tumors are mesenchymal tumors consisting of blood vessels, smooth muscles and fat cells. The patient received anti-proliferative treatment with Afinitor, a mammalian target of rapamycin (mTOR) inhibitor, and was referred again one month after onset of therapy for early response assessment. The follow-up F-FDG PET/CT scan showed a nearly complete resolution of the previously detected adrenal mass, with very low tracer uptake and a decrease in its functional volume. Fluorine- 18-FDG PET/CT can be used for treatment response evaluation of angiomyolipoma treated with mTOR-inhibitors.