Happle-Tinschert syndrome. Segmentally arranged basaloid follicular hamartomas, linear atrophoderma with hypo- and hyperpigmentation, enamel defects, ipsilateral hypertrichosis, and skeletal and cerebral anomalies.

Recently, Happle and Tinschert [Acta Derm Venereol 2008;88:382-387] described the case of a multisystem birth defect with segmentally arranged basaloid follicular hamartomas associated with extracutaneous defects in the form of short leg, polydactyly and hypoplastic teeth. The authors presented a comprehensive overview of 8 similar cases reported under various designations, and provided evidence that this syndrome includes various additional defects of the bones, teeth and brain. Here, a further typical case is reported, and it is emphasized that this phenotype should no longer be categorized as 'basal cell nevus syndrome', and thus be confused with the nevoid basal cell carcinoma syndrome of Gorlin [Cancer 1965;18:89-104]. A 7-year-old boy had multiple whitish and some scattered brownish basaloid follicular hamartomas involving the right side of his body in a systematized pattern following the lines of Blaschko. These lesions had been present since birth. They were hairless and conspicuously hypopigmented. In addition, enamel defects and mild webbing of the first and second right toes were noted. At the age of 5 years, the boy developed a medulloblastoma that originated from the ipsilateral paramedian vermis region. The tumor was surgically removed, and subsequently radiotherapy and chemotherapy were applied. Analysis of blood DNA did not reveal any Patched mutation. The molecular basis of the disorder remains to be elucidated. From this case and from 9 similar cases reported in the literature, the spectrum of a distinct phenotype is delineated, and the eponymic designation Happle-Tinschert syndrome is proposed.