Renal Ewing tumors.

BACKGROUND Renal Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) is extremely rare. Clinical symptoms are nonspecific presenting abdominal pain, palpable mass, and hematuria. Owing to advanced technology demonstrating the ES-specific EWS/ETS translocation, this differential diagnosis has become feasible. PATIENTS AND METHODS The German database of GPOH Ewing's sarcoma trials from 1980 to 2009 was searched for kidney as primary site. Twenty-four patients were identified and analyzed. The median time of observation was 3.71 years (range 0.27-8.75 years). Additionally, we carried out a Medline search for renal ES/PNET. RESULTS The median age was 24.9 years (range 11-60 years). In 37.5%, patients presented with primary metastases. Tumor thrombi in the adjacent renal vessels occurred in 56.2%. In 90.9%, rearrangements of t(11;22) were found. All patients received a combined chemotherapy according to the EURO-E.W.I.N.G.99 protocol. In accordance, local control consisted predominantly of combined modality surgery and radiation (47%). At 3 years, overall survival (OS) was 0.80 (SE = 0.09), and event-free survival (EFS) 0.66 (SE = 0.11). CONCLUSIONS ES/PNET should be considered in the differential diagnosis of renal tumors. Patients with renal ES/PNET respond to and benefit from conventional ES treatment according to ES study protocols. Therefore, an accurate diagnostic approach and a guideline-adapted therapy should be facilitated.