Background/purpose: Primitive neuroectodermal tumours (PNET) are rare tumours sharing similar histology, immunohistochemistry, and cytogenetics to Ewing's sarcomas. The aim of the study was to document the effect of site of origin and the completeness of surgical excision on the outcome in infants and children with PNET.
Methods: All patients (n = 26) with PNET treated in our hospital during the last 6 years were included in the study. The diagnosis was based on the histopathologic findings and a positive MIC2 antibody test. The tumours were classified according to the Intergroup Rhabdomyosarcoma Study III, and were treated according to the UKEESG protocol for Ewing's Sarcoma.
Results: Complete remission (CR) was achieved in 52% of the patients completing their chemotherapy. Overall, survival was 42% (11 of 26). Tumours from the paraspinal and scapula areas responded relatively well (CR, 83%), whereas abdominal PNET did not respond to treatment. Tumours arising from the head, neck, or chest had an intermediate prognosis (37% survival). Three of the 10 patients who had a complete excision of the tumour died of progressive disease.
Conclusions: Complete surgical excision reduced the risk of local recurrence but did not prevent metastatic spread. These data indicate that PNET have a worse prognosis and different favourable sites than other sarcomas. New treatment strategies are necessary for these rare tumours.