Abstract
Adult T-cell leukemia/lymphoma (ATLL) is an aggressive T-cell malignancy associated with human T-lymphotropic virus 1 (HTLV-1) infection. In this case study, we present a male patient diagnosed with CD30-positive ATLL, a rare pathological subtype characterized by the presence of HTLV-1-infected Hodgkin and Reed-Sternberg-like (HRS-like) cells. The patient was considered unsuitable for intensive chemotherapy due to advanced age and severe comorbidities. Consequently, the patient was treated with brentuximab vedotin (BV) monotherapy. Following five cycles of BV, the patient achieved partial remission (PR) without significant adverse events. Eight months have passed since the end of treatment, and the disease has not progressed. The positive results of this study suggest that BV monotherapy could be considered a viable treatment option for older or frail patients with CD30-positive ATL, particularly those with HTLV-1-infected HRS-like cells, who may not be able to tolerate standard multi-agent chemotherapy.