Multiple familial basal cell carcinomas including a case of segmental manifestation.

BACKGROUND: A tendency to develop multiple basal cell carcinomas at an early age is a characteristic feature of some rare hereditary disorders; moreover, multiple basal cell carcinomas are sometimes observed as a corollary of familial basaloid follicular hamartomas or familial multiple trichoepitheliomas. OBSERVATION: We report 3 cases of multiple basal cell carcinomas involving 3 successive generations of a family, with a segmental manifestation of lesions in one of these patients. No additional cutaneous or extracutaneous anomalies were found.
CONCLUSIONS: We hypothesize that a gene mutation may have caused the tumors observed in this family as an autosomal dominant trait. The segmental arrangement of tumors may reflect loss of heterozygosity: at an early stage of embryogenesis, a postzygotic mutation would give rise to a population of cells either homozygous or hemizygous for the underlying gene. The segmental arrangement following the lines of Blaschko would visualize the dorsoventral proliferation of a cell clone characterized by loss of the corresponding normal allele. Copyright 2000 S. Karger AG, Basel