Primitive neuroectodermal tumor of the kidney: a single institute series of 16 patients.

Objectives: Primitive neuroectodermal tumor (PNET) of the kidney is a rare entity, the diagnosis usually being made at histopathology. Few cases reported in literature revealed a variable presentation and an aggressive behavior. The purpose of our study was to review our experience in diagnosis and the management of patients with renal PNET.

Methods: The records of 16 patients of renal PNET treated between 1995 and 2003 were reviewed retrospectively and our data compared with the literature.

Results: There were 10 male and 6 female patients with median age of 27 years. At presentation, 10 patients (63%) had localized disease, 5 (31%) had metastatic disease and 1 (6%) had locally advanced disease. The presence of Homer-Wright type rosettes on hematoxylin and eosin staining and CD99 (cluster differentiation) products positivity on immunohistochemistry supported the diagnosis. Radical nephrectomy was performed in operable cases and all patients received chemotherapy. Nine patients received adjuvant radiotherapy to the renal bed. Median follow-up was 31 months (range 4 to 92). Overall median survival was 40 months with 3- and 5-year survival of 60% and 42%, respectively.

Conclusions: The diagnosis of renal PNET must be considered in young patients presenting with renal mass. Standard therapy consists of combination of surgical resection, postoperative irradiation and chemotherapy. Chemotherapy regimen used is either RCT II (round cell tumor) protocol or EFT 2001 (Ewing's family of tumors) protocol. However, further studies are required to validate the appropriate chemotherapy protocol.