A case of basal cell nevus syndrome with a SUFU mutation

Abstract

Basal cell nevus syndrome (Gorlin syndrome) is a rare genetic condition characterized by multiple basal cell carcinomas, often arising before age 20.  Most cases result from a mutation in the patched 1 gene—part of the sonic hedgehog pathway. Rarely, this condition is related to a suppressor of fused gene mutation, which occurs downstream from Smoothened, and is unresponsive to Smoothened inhibitors including vismodegib and sonidegib. Notably, basal cell nevus syndrome, secondary to a suppressor of fused gene mutation, is associated with a higher incidence of childhood medulloblastoma with implications for the patient and offspring. 

A 72-year-old man with pearly papules coalescing into plaques across the nose and cheeks presented. The lesions had appeared as a teenager, and the patient reported his sister had similar lesions. Five biopsies, reviewed by three dermatopathologists, were consistent with basal cell carcinoma. Genetic testing was negative for patched 1 and patched 2 mutations but positive for a heterozygous suppressor of fused mutation. Patients with basal cell nevus syndrome should be treated with surgical excision, counseled on sun protection, screened and monitored for complications, and treated with vismodegib (if associated with patched 1 mutation) or itraconazole (if associated with suppressor of fused mutation).