Whole-genome sequencing studies have recently identified a quarter of cases of the rare childhood brainstem tumor diffuse intrinsic pontine glioma to harbor somatic mutations in ACVR1. This gene encodes the type I bone morphogenic protein receptor ALK2, with the residues affected identical to those that, when mutated in the germline, give rise to the congenital malformation syndrome fibrodysplasia ossificans progressiva (FOP), resulting in the transformation of soft tissue into bone. This unexpected link points toward the importance of developmental biology processes in tumorigenesis and provides an extensive experience in mechanistic understanding and drug development hard-won by FOP researchers to pediatric neurooncology. Here, we review the literature in both fields and identify potential areas for collaboration and rapid advancement for patients of both diseases.