Unicystic ameloblastoma associated with the novel K729M PTCH1 mutation in a patient with nevoid basal cell carcinoma (Gorlin) syndrome.

Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by a very wide spectrum of clinical signs and symptoms. Here, we report an unusual case of NBCCS in a 38-year-old man with an early onset of clinical signs and symptoms and an associated unicystic ameloblastoma, histopathologically showing basaloid differentiation and intraluminal growth. The odontogenic tumor was surgically enucleated and recurred at the follow-up at 14 months. The proband and his child were identified as gene carriers of the novel K729M PTCH1 missense mutation; other first- and second-degree relatives presented clinical features of NBCCS. Only five other cases of association between ameloblastoma and NBCCS have been reported so far, suggesting that PTCH1 missense mutation might take part in the pathogenesis of keratocystic odontogenic tumors (KCOTs) as well as ameloblastomas.