Palmoplantar hyperkeratotic plaques. Hyperkeratotic mycosis fungoides restricted to the palms and soles

Drug-Induced Lichenoid Dermatitis with Histopathologic Features of Mycosis Fungoides in a Patient with Psoriasis

Background:

With recent advancements in the understanding of psoriasis, treatment has evolved toward more targeted therapy in the form of biologics. Although generally safe and well tolerated, various adverse reactions may occur with the use of biologics.

Objectives:

The objective of this article is to present a case of a biologic-induced drug eruption initially presenting with histopathologic features of mycosis fungoides (MF).

Methods and Results:

A 47-year-old male presented with an extensive erythematous macular eruption approximately 14 hours after a single dose of etanercept. Histopathology initially revealed a lichenoid dermatitis with features of MF, but immunohistopathology later refuted the presence of MF.

Conclusions:

It is important for clinicians to be aware that adverse cutaneous reactions with biologic therapy may initially present with histopathologic features of MF.

Mycosis fungoides mimicking inflammatory linear verrucous epidermal nevus

We experienced an unusual case of mycosis fungoides with the clinical and histological features mimicking inflammatory linear verrucous epidermal nevus (ILVEN) in an 11-year-old boy. Localized linear multiple pruritic verrucous confluent papules and plaques appeared on the his left elbow, forearm and hand for 7 months. Skin biopsies showed characteristic findings of mycosis fungoides (e.g. Pautrier's microabscesses, follicular epitheliotropism, wiry bundles of collagen, etc.). T-cell receptor gene rearrangement analysis in the lesional skin demonstrated rearrangement of the gamma chain. RePUVA (systemic PUVA with retinoic acid) therapy improved his skin lesions and pruritus, but these progressed after discontinuation of treatment. Thus, lesions mimicking ILVEN can be an unusual and potentially misleading presentation of mycosis fungoides.