Subcutaneous fatty tissue metastasis from renal cell carcinoma detected with fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography and magnetic resonance imaging

A patient who had undergone left radical nephrectomy 11 years ago for renal cell carcinoma (RCC) was referred to our clinic for restaging. Fluorine-18 fluorodeoxyglucose (F18-FDG) positron emission tomography/computed tomography (F18-FDG PET/CT) showed hypometabolic area in left frontal region of the brain and increased FDG uptake in the subcutaneous fatty tissues of the right thigh. Histopathological examination of the biopsy material from the left frontal region and right gluteal region revealed metastasis of clear cell type RCC. Seven months later, a magnetic resonance ımaging (MRI) of right cruris showed a contrast-enhancing lesion with a diameter of 3.5 cm, located at the subcutaneous area of posterior part of right cruris. A concomitant F18-FDG PET/CT detected an increased FDG uptake focus in the proximal third of right cruris adjacent to the muscle planes and this finding was consistent with metastasis of RCC.