title: Mycosis fungoides associated with unusual epidermal hyperplasia.
abstract: A 58-year-old white woman presented with widespread pruritic brownish plaques and hyperpigmented flexural lesions with a velvety appearance. On histopathological examination, the macules were diagnostic of mycosis fungoides, plaque stage, and the flexural lesions showed epidermal hyperplasia with a seborrhoeic keratosis-like appearance. There was intense mucin deposition and marked reduction of elastic fibres in the papillary dermis, as well as a moderately dense dermal lymphoid infiltrate composed of CD4+ T cells with occasional atypia and focal epidermotropism. The clinical and pathological manifestations of cutaneous T-cell lymphomas, including mycosis fungoides (MF), may show considerable variation. Apart from the three classic stages, a number of unusual clinical presentations and a broad spectrum of histopathological findings have been reported in the literature. In this report, a case of MF, plaque stage, with flexural lesions clinically reminiscent of (pseudo)acanthosis nigricans is presented. On histopathological examination, there was epidermal hyperplasia with a seborrhoeic keratosis-like appearance, with intense deposition of mucin and marked reduction of elastic fibres in the papillary dermis, together with a lymphoid infiltrate composed mainly of CD4+ cells with occasional atypia and epidermotropism. Cytokines produced by the lymphocytes in the infiltrate might account for the epithelial and dermal changes that characterize this peculiar variant of MF.
authors.affiliation: Department of Dermatology, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Puig
authors.forename: E
authors.initials: E
authors.lastname: Musulén
authors.forename: M T
authors.initials: MT
authors.lastname: Fernández-Figueras
authors.forename: J
authors.initials: J
authors.lastname: Miralles
authors.forename: D
authors.initials: D
authors.lastname: Sitjas
authors.forename: J M
authors.initials: JM
authors.lastname: De Moragas
mesh_terms: D005260:Female; D006801:Humans; D006965:Hyperplasia / Q000150:complications / Q000473:pathology; D008875:Middle Aged; D009182:Mycosis Fungoides / Q000150:complications* / Q000473:pathology; D012867:Skin / Q000473:pathology*; D012878:Skin Neoplasms / Q000150:complications* / Q000473:pathology