A focal lesion in the falx cerebri: Harbinger of classic stage 4 neuroblastoma in an infant cured despite residual disease after minimal therapy.

An asymptomatic 11-week-old male received no treatment after he was classified as having a suspected atypical form of MYCN-nonamplified hyperdiploid stage 4S neuroblastoma (NB), with masses in an adrenal gland, subcutaneous tissues, and the falx cerebri. Within 2 months, however, disease progressed in dura and bone marrow. Two cycles of low-dose chemotherapy achieved a partial response; treatment was discontinued. Complete remission was documented 24 weeks post-cycle 2, and has continued >6 years. The falx cerebri probably does not represent an atypical site for stage 4S NB, but stage 4 NB with favorable biology is sometimes curable with minimal therapy.