Objective: Primitive neuroectodermal tumors (PNET) of the kidney are rare and highly aggressive malignancies. The purpose of our study was to present information about the management of patients with metastatic disease.
Methods: The records of 2 patients (30-year-old female and 32-year-old male) with metastatic PNET of the kidney were reviewed and our data compared with the literature.
Results: Neither clinical evaluation nor radiological methods allowed to distinguish PNET from renal cell carcinoma. Immunohistochemistry revealed strong positivity for CD99 in tumor 1 and weak positivity for NSE and vimentin in both tumors. In tumor 2, EWS/FLI1 translocation was detected by RT-PCR. Patient 1 underwent nephrectomy, seven cycles of polychemotherapy, two cycles of high-dose chemotherapy, autologous bone marrow rescue, radiotherapy of suspicious skeletal foci and is without evidence of recurrent disease 28 months after therapy. Patient 2 underwent six cycles of polychemotherapy, nephrectomy, high-dose chemotherapy with cyclophosphamide and abdominal radiotherapy. Because of relapse high-dose chemotherapy with stem cell rescue was not performed. He underwent three further cycles of polychemotherapy and died one year after diagnosis due to cerebral metastasis.
Conclusions: The diagnosis of renal PNET must be considered in young patients with renal neoplasm, particularly those with advanced disease at presentation. Achieving exact diagnosis has important clinical consequences because polychemotherapy and high-dose chemotherapy may lead to dramatic tumor reduction or even complete remission.