Among intracranial embryonal tumors, genetic/epigenetic analysis can help unveil the molecular background. Herein, we report a case of a cerebellar pontine angular embryonic tumor complicated by Cowden syndrome in an infant. The tumor radiologically lacked evidence of interaction with the cerebellum and appeared to show continuity with the pons. Pathological appearance was similar to that of a medulloblastoma with extensive nodularity. DNA methylation analysis indicated that the tumor was a “medulloblastoma, sonic hedgehog-activated” with a substantial confidence. Although the diagnosis deviated from the definition of medulloblastoma, clinical, pathological and molecular data suggested that it was an “ectopic” medulloblastoma.