The development of fulminant type 1 diabetes during chemotherapy for rectal cancer.

A 34-year-old man with a history of rectal cancer was receiving oral chemotherapy [tegafur-uracil (UFT) with leucovorin]. He visited our hospital due to nausea and abdominal pain, and his laboratory data revealed the presence of urinary ketones, hyperglycemia and high anion gap metabolic acidosis, and HbA1c level of 6.8%. Accordingly, we diagnosed fulminant type 1 diabetes. The development of fulminant type 1 diabetes during chemotherapy for malignancy is a rare, but potentially fatal condition. Therefore, clinicians should consider diabetic ketoacidosis in the differential diagnosis when examining chemotherapy patients who present with gastrointestinal symptoms.