Peripheral neuroectodermal tumour of the kidney (Ewing's sarcoma): Restaging with (18)F-fluorodeoxyglucose (FDG)-PET/CT.

Primitive peripheral neuroectodermal tumour and Ewing's sarcoma (PNET/EWS) were originally described as two distinct pathologic entities, although both share common stem-cell precursor and unique chromosomal abnormality. Although its incidence has increased recently, its share in all sarcomas is 1%. It is usually seen in men and women in their twenties. We present a case of a 38-year-old woman with a left renal mass detected incidentally. Magnetic resonance imaging revealed a centrally located hypervascular renal mass with diameter of 6 cm with non-homogenous contrast enhancement containing necrotic and calcific areas. The patient was diagnosed as having PNET/EWS by histopathological examination following radical nephrectomy. Para-aortic lymph node metastasis was found on imaging by (18)F-fluorodeoxyglucose (FDG)-positron-emission tomography/computed tomography (PET/CT).