Monozygotic siblings discordant for neuroblastoma: etiologic implications.

Although rarely reported, neuroblastoma in monozygotic siblings merits attention because study of its features may aid in elucidating mechanisms of tumorigenesis. We describe disseminated neuroblastoma in one of monozygotic triplets, including both documentation of monozygosity and long-term follow-up of the unaffected co-twins. Information from reports of monozygotic twins concordant and discordant for neuroblastoma reinforces the hypothesis that hereditary factors may be predominant in neuroblastoma diagnosed in infants, whereas nonheritable random mutational genetic events may be more important in neuroblastoma diagnosed after infancy.