Pityriasis lichenoides-like mycosis fungoides in children.

We report three children with clinical features of pityriasis lichenoides (scaly red to brown papules and macules) in whom there were histopathological findings of mycosis fungoides (disproportionate epidermotropism, Pautrier's microabscesses, and wiry and coarse collagen bundles). Immunohistochemical staining revealed a prevalence of T lymphocytes in the infiltrate. T-cell receptor gene rearrangement analysis in lesional skin demonstrated rearrangement of the gamma chain in all cases. Human T-cell lymphotropic virus type 1 serology was negative in the two patients in whom this test was performed. Thus, lesions resembling pityriasis lichenoides can be an unusual and potentially misleading presentation of mycosis fungoides.