Severe Presentation of De Novo Type II Diabetes in Abiraterone and Prednisone Therapy.

Abiraterone acetate is a widely used androgen biosynthesis inhibitor for the treatment of metastatic castration-resistant prostate cancer. It is usually co-administered with low-dose prednisone to counteract mineralocorticoid excess. While adverse effects such as hypertension, hypokalemia, and fluid retention are well recognized, hyperglycemia is a rare and underreported complication. We describe a case of a 77-year-old man with no prior history of diabetes who presented with acute severe symptomatic hyperglycemia after several months of treatment with abiraterone and low-dose prednisone. His laboratory workup revealed a serum glucose level of 431 mg/dL and hemoglobin A1c of 11.3%. The patient was managed with insulin therapy and later transitioned to metformin and basal insulin upon discharge. The temporal relationship between abiraterone initiation and the onset of dysglycemia raises concern for a potential causative link. Given the impact of hyperglycemia on cancer outcomes and quality of life, this case underscores the need for increased clinical awareness and routine glucose monitoring in patients treated with abiraterone and corticosteroids.