Primitive neuroectodermal tumor: Rare, highly aggressive differential diagnosis in urologic malignancies

A large and metastatic primitive neuroectodermal tumor of the kidney

“…Renal PNET can manifest in a wide age range; however, most of the patients are observed in a range of 10-39 years. [4] Ellinger et al [4] reported that patients with renal PNET complained about pain (85%), palpable masses (60%), and hematuria (37%), similar to a classic triad of RCC. The advanced disease rate was 57.6% and the most frequent metastases were lymph node (25%), lung (20%), and liver (14%).…”

“…Despite multimodal treatment protocols combining surgery, chemotherapy, and radiotherapy to the renal bed, prognosis is poor with a 5-year disease-free survival rate of 45%-55%. [2,4] Before the routine use of adjuvant chemotherapy, the 5-year survival rate in patients with Ewing family tumors were <10%. [2] Unfortunately, our patient died in the early postoperative period because of an advanced disease.…”

PNET/Ewing’s sarcoma of the kidney: imaging findings in two cases

“…The CT-appearance of PNET/Ewing's sarcoma is characterized by a large renal mass with heterogeneous contrast enhancement, necrotic or hemorrhagic areas and sometimes calcifications (1). However, the radiological features are indistinguishable from other primary, malignant renal parenchymal tumors or urothelial cancer (1,2,4). Other tumors that may be considered in the differential 2 postcontrast scans including axial, coronal and sagittal multiplanar reconstructions in the venous phase.…”

“…The abdominal CT findings were retrospectively reviewed. In both cases unenhanced CT scans were performed followed by at least PNET/Ewing's sarcoma of the kidney typically occurs in adolescents and young adults with a reported median age of 24-27 years (1,3). The clinical presentation is variable and aspecific with patients complaining of flank pain (85%), palpable abdominal mass (60%), hematuria (37%) or weight loss (8%) (1,4).…”

“…Microscopically PNET/ Ewing's sarcoma is characterized by small round tumor cells with typical Homer-Wright rosette-like growth pattern (2,3,5). Overexpression of the surface membrane CD99 is a suggestive diagnostic clue on immunohistochemistry but the final diagnosis of PNET/Ewing's sarcoma is based on cytogenetic analysis (FISH and PCR) revealing EWS gene rearrangement, including the t(11;22)(q24;q12) translocation (1)(2)(3)5). It remains unclear whether or not Ewing's sarcoma and PNET are distinct entities since they have similar biologic, pathological and molecular findings (2,5).…”