Adnexotropic and granulomatous mycosis fungoides following TNF‐α inhibitor treatment

Abstract

AbstractRecent publications have documented an increased prevalence of cutaneous T‐cell lymphoma (CTCL) in patients undergoing tumor necrosis factor alpha (TNF‐α) inhibitor therapy. Herein, we present an uncommon manifestation of mycosis fungoides (MF) with unique pathological findings after the initiation of adalimumab therapy for the treatment of psoriasis. One year after starting treatment, the patient noticed a slowly growing, eroded plaque on the left cheek, the biopsy of which demonstrated mixed granulomatous and adnexotropic lymphocytic infiltrate with features characteristics of MF. In the following months, the patient developed pink‐ and violet‐colored scaly plaques on the right posterior upper arm and right medial upper arm. Biopsy of these plaques also revealed findings compatible with MF. T‐cell receptor (TCR) clonality studies by PCR revealed identical T‐cell clones in the samples obtained from the cheek, right posterior upper arm, and right medial upper arm. TCR clonality studies of a long‐standing psoriatic plaque on the right thigh failed to reveal similar T‐cell clones. Blurring of histopathologic presentation by TNF‐α inhibitors could greatly complicate the identification of MF subtypes. Providers treating patients with TNF‐α inhibitors must be aware of the risk of cutaneous lymphoma development and the potential deviations from their expected presentations. In patients without an initial biopsy, the possibility of pre‐existing CTCL with psoriasiform presentation should be considered.