Neuroblastoma Occurring in Nijmegen Breakage Syndrome.

Nijmegen breakage syndrome (NBS) is a rare primary immunodeficiency disease due to a pathogenic variant in the NBN gene causing impaired DNA repair and increased predisposition for lymphoid malignancy. By contrast, solid tumors have been rarely reported. Neuroblastoma (NB) is a rare childhood solid tumor, associated with the worse outcome if MYCN oncogene is amplified. We describe 2 young pediatric patients with NBS who developed high-risk NB. The first patient died shortly after chemotherapy was introduced. The second patient successfully received modified chemotherapy resulting in clinical remission lasting 2 years after an initial diagnosis of NB.