Brentuximab Vedotin‐Induced Rash Sparing CD30‐Positive Mycosis Fungoides Lesions

ABSTRACT Brentuximab vedotin (BV) is an effective treatment for CD30‐positive lymphomas, including mycosis fungoides (MF). However, its use can be associated with various cutaneous adverse effects, including rashes. This case describes a 60‐year‐old male with stage IIB MF who developed a drug‐induced erythematous rash after three infusions of BV. Remarkably, the rash spared pre‐existing MF lesions, which remained demarcated and flattened. Histopathological evaluation confirmed a drug‐induced lichenoid reaction in the affected skin, while the MF lesions exhibited residual disease with CD30‐positive atypical T‐cells. Systemic corticosteroids led to resolution of the rash, and BV therapy was temporarily paused. The patient achieved complete remission of MF with only residual hyperpigmentation at the 10‐month follow‐up. This case highlights a unique interaction between BV and the neoplastic skin environment, warranting further investigation into the underlying mechanisms.