Abstract
A 62-year-old man presented with left ear pain, sensorineural hearing loss, and high-grade fever. Peripheral blood tests revealed abnormal blood cells, prompting further investigation that led to a diagnosis of myelodysplastic syndromes (MDS) with paraneoplastic vasculitis. Since initial treatment with azacitidine (Aza) was insufficient, additional immunosuppressive therapy was required. The disease was effectively controlled with a combination of Aza, prednisolone, and azathioprine, with no relapse for 10 treatment courses. However, the disease later transformed into acute myeloid leukemia. This case highlights the efficacy and feasibility of additional treatment with steroids and azathioprine for refractory paraneoplastic vasculitis associated with MDS, while emphasizing the need for careful monitoring of leukemic progression under prolonged immunosuppression.