After the first transurethral resection due to bladder tumor 3 years ago, glycemic control suddenly deteriorated, and insulin requirement increased to 2.3 IU/kg/d, despite FPG: 560 mg/dL (31.1 mmol/L), HbA1c: 13.4% (123 mmol/mol) levels. Here, INS is linked to urinary bladder neoplasm.