Novel nonsense GNAS mutation in a 14-month-old boy with plate-like osteoma cutis and medulloblastoma

Plate‐like osteoma cutis (PLOC) is a dermatological disorder characterized by superficial ossification and rarely occurs without any underlying tissue abnormalities or pre‐existing calcification. The hereditary form of PLOC is mainly due to inactivating mutation in the GNAS gene. Inactivating mutation of the GNAS gene is associated with several diseases, which commonly manifest heterotopic ossification and hormonal resistance; however, the development of malignant neoplasm has never been reported. Herein, we report a case of a patient with a novel nonsense mutation in the GNAS gene, who presented with concurrent PLOC and medulloblastoma.