TP53 and skin basal cell carcinoma: According to the revised WHO classification of tumors of the CNS 2016, the tumor classifies as desmoplastic/nodular, SHH-activated, TP53 wild-type MB (WHO grade IV).30 At age 16 years, the patient developed her first basal-cell carcinoma (BCC) and has subsequently gone on to develop 10 more BCCs, all within the radiation field and all amenable to surgical removal.