The unexpected guest: Cytotoxic, pseudolymphoma‐like reaction at the site of primary cutaneous follicle centre B‐cell lymphoma in a patient receiving secukinumab for psoriasis.

This article presents a unique case of a patient with primary cutaneous follicle centre B-cell lymphoma (PCFCCL) who developed a T-cell pseudolymphoma while receiving secukinumab for psoriasis treatment. The patient initially received local radiotherapy for PCFCCL and subsequently developed psoriasis. After starting secukinumab, the patient experienced rapid growth and ulceration of the previously irradiated lesion, which was biopsied and revealed a residual PCFCCL component along with a dense proliferation of small-to-medium-sized lymphocytes. The authors suggest that the pseudolymphoma may have been triggered by secukinumab. This case highlights the complex interplay between tumor and self-immunity and the role of lymphoma-specific T cells. [Extracted from the article]