Is Primitive Neuroectodermal Tumor of the Kidney a Distinct Entity?

Background: Primitive neuroectodermal tumors (PNETs) constitute a family of neoplasms of presumed neuroectodermal origin, most often presenting as bone or soft tissue masses in the trunk or axial skeleton in adolescents and young adults. As a soft tissue neoplasm, PNET arising in the kidney has not been well described, with only three cases previously reported.

Methods: Four patients with PNET of the kidney were diagnosed and treated at St. Jude Children's Research Hospital. The authors reviewed the clinical, radiologic, and pathologic features and outcomes of these cases and of those previously described.

Results: The authors' patients were age 4-20 years. They presented with unilateral renal masses and metastatic disease in the lymph nodes (three patients), lungs (three patients), bone (two patients), liver (one patient), and bone marrow (one patient). Treatment included surgery, radiotherapy, and multiagent chemotherapy. Three of the patients died of progressive disease within 14 months of diagnosis. Features and outcomes were similar to those of the three previously reported cases.

Conclusions: PNET of the kidney appears to be a distinct entity. Although rare, it must be included in the differential diagnosis of renal tumors in children and young adults. Patients usually present with advanced disease and show poor response to combined-modality therapy.