Psoriasiform eruption is an uncommon cutaneous immune-related adverse event (irAE) associated with anti-PD-1 therapy, and its rapid recurrence upon switching to a different anti-PD-1 agent is a scarcely documented phenomenon. We report the case of a 59-year-old man with stage IIB lung adenocarcinoma who developed a pruritic, scaly eruption after his fourth cycle of pembrolizumab. Histopathological examination confirmed a diagnosis of grade 2 psoriasiform dermatitis according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. The initial episode was resolved with systemic corticosteroids. However, upon switching anti-PD-1 therapy to tislelizumab, a similar but more widespread eruption recurred rapidly within a week. The recurrence was successfully managed with topical corticosteroid and antihistamines, and the anti-PD-1 therapy was subsequently discontinued. During the 3-year follow-up after discontinuation, the patient’s skin lesions resolved completely with no recurrence, and no tumor progression was observed. The reduced latency of psoriasiform dermatitis recurrence upon anti-PD-1 inhibitor rechallenge suggests a memory T cell–driven immune response. It also highlights that such irAEs were observed with the two PD-1 inhibitors pembrolizumab and tislelizumab used in this case and can be effectively managed. In this case, tumor progression was not observed after treatment cessation, although causality cannot be inferred.
Chi et al. (Wed,) studied this question.