Renal displacement caused by a supradiaphragmatic, paraspinal Ewing-like sarcoma and simulating an adrenal mass

Two cases of children with paravertebral soft-tissue masses that histologically resembled Ewing sarcoma of bone are reported. In both cases the mass was located immediately above the diaphragm. It depressed the posterior segment of the diaphragm and indirectly caused displacement of the ipsilateral kidney, thus simulating an adrenal mass on excretory urography. The anatomic reasons for this phenomenon and the main features of the tumor are discussed.