The poikiloderma of Rothmund-Thomson syndrome: changes in Langerhans cell morphology and distribution.

A black girl with the Rothmund-Thomson syndrome is presented. Immunophenotyping of subpopulations of immunocompetent cells in a biopsy of an atrophic hyperpigmented skin lesion revealed sparsity and unusual distribution of epidermal Langerhans cells. These cells were mainly located in the basal layer of the epidermis and did not show the usual dendritic pattern. Impressive immunoreactivity of the dermal infiltrate was observed by anti-HLA-DR staining. The changes in Langerhans cell morphology and distribution may indicate functional impairment of the up-regulating arm of skin immunity.