Peripheral primitive neuroectodermal tumor: challenge for multimodal treatment.

The primitive neuroectodermal tumor (PNET) is an extremely aggressive soft tissue neoplasm that occurs in children and adolescents. We retrospectively reviewed our therapeutic experience with a multidisciplinary approach, combining surgery, chemotherapy, and radiation therapy. Treatment of PNET was carried out in compliance with the soft tissue protocol (CWS) from the German Society of Pediatric Oncology. Biopsy-proven diagnosis was followed by chemotherapy, which in all cases led to partial remission, allowing excision of the remainder of the tumor without mutilation. After excision, irradiation of the tumor site and two further sequences of chemotherapy were performed. When PNET of the paravertebral region caused symptoms of paralysis and immediate surgery was required, postoperative chemotherapy, a second-look operation, and irradiation were undertaken. Between 1986 and 1998 we treated 13 patients (median age 15 years). In five patients the PNET originated from the chest wall and in eight patients from the paravertebral and retroperitoneal region. Five patients died after 20 months on average, and the remaining eight patients are in full remission after 7, 16, 46, 55, 70, 74, 75, and 115 months, respectively. Close cooperation between surgeons and their pediatric and radiotherapy colleagues is obligatory when treating PNET. Chemotherapy as the first stage is mandatory to avoid a mutilating surgical procedure and intraoperative tumor cell dissemination.