骨外性 Ewing 肉腫 (PNET) 6例の治療経験

抄録

We clinicopathologically analyzed six cases of extraskeletal Ewing's sarcoma (ES) and primitive neuroectodermal tumor (PNET) treated from 1978 to 1996, and found that cases which showed rosettes histologically have better prognosis. The average age of the 2 male and 4 female patients was 21 years. Tumors were located in the thigh (3 patients), lower leg, back, and flank. 5 patients showed localized disease in diagnosis and 1 had metastases. All patients underwent surgical treatment and adjunctive therapy (radiation or chemotherapy, or both). Histologically, Homer Wright-type rosettes were seen in 3 patients who were all alive for following period. The 5-year overall survival was 66.7%. Now ES and PNET are thought to belong to a single group of tumors with neuroectodermal features,
ES does not reveal neural features in situ, while PNET shows distinct neural differentiation even in histological sections. This report did not differentiate between ES and PNET, because the same therapy was performed in both tumors, and also the prognostic significance of PNET or neural differentiation in ES is controversial. The 6 cases in this report demonstrate that the neural features in ES (PNET) show good prognosis.