Cutis tricolor: congenital hyper- and hypopigmented lesions in a background of normal skin with and without associated systemic features: further expansion of the phenotype.

UNLABELLED: The term cutis tricolor describes the uncommon co-existence of congenital hyper- and hypopigmented macules, in close proximity to each other, in a background of normal skin so far seen in a 17-year-old patient with various other congenital defects. The suggested explanation for this phenomenon is allelic twin spotting. We report on two boys, aged 6 and 11 years, with an unusual combination of three different degrees of pigmentation, one of whom had in addition, psychomotor delay, dysmorphic features, musculoskeletal abnormalities and subcortical and periventricular white matter high signal lesions on brain neuroimaging. In both cases a search for mosaicism in peripheral blood lymphocytes and cultured fibroblasts was negative. In contrast to the previously reported case, the two children had large streaks or patches of hyper- and hypopigmented skin lesions, in close proximity to each other, involving large areas of the body. The rest of the skin had a normal intermediate pigmentation.
CONCLUSION: This combination of three degrees of pigmentation in association with systemic defects in one child and the lack of such association in the other confirms and further expands the clinical phenotype of cutis tricolor.