Maturing neuroblastoma and ganglioneuroblastoma: a study of four cases with long survival.

A retrospective study of four tumours of the peripheral nervous system originally diagnosed as neuroblastomas or ganglioneuroblastomas has been made. The patients have all survived since the original diagnosis. Evidence of residual tumour was seen only in one patient, and was associated with evidence of increasing histological differentiation over a period of time. Maturation of primitive cell types is known to alter the prognosis of neuroblastic tumours. It is suggested first, that even minimal evidence of maturation indicates a better prognosis. Second, that evidence of maturation may be uneven, small areas occurring in otherwise totally undifferentiated tumours, or, immature areas remaining even in apparently benign fully mature tumours; if these areas show maturation the prognosis remains good and the tumour should not be confused with a composite ganglioneuroblastoma. Third, that maturing tumours may behave in a malignant fashion, invade and metastasise, but but with maturation of the primary tumour and its metastases the ultimate prognosis may be better than the initial behaviour suggests.