2023 Volume 66 Issue 2 Pages 151-156
Pheochromocytoma is known to be associated with impaired glucose tolerance, but it rarely leads to diabetic ketoacidosis (DKA). We herein report a patient with asymptomatic pheochromocytoma and DKA who was diagnosed with an adrenal incidentaloma. A 52-year-old man with diabetes was admitted for DKA. Pheochromocytoma was not suspected because the patient had no history of hypertension, physical examination findings were unremarkable, and laboratory results were almost normal except for the presence of an adrenal tumor with a CT value of 48.2 Hounsfield units (HU). After the patient had recovered from DKA, we performed a glucagon challenge test and found that the patient was insulin-dependent. After discharge, 123I-metaiodobenzylguanidine (123I-MIBG) scintigraphy was performed, and pheochromocytoma was diagnosed. After tumor resection, the insulin secretory capacity was re-examined, and the patient was insulin-independent. Reports have been published concerning two patients with pheochromocytoma who developed DKA. In both cases, the adrenal tumor was considered to be non-functioning, and notably, both patients were taking a sodium-glucose co-transporter 2 (SGLT2) inhibitor for treatment of diabetes. The present case was similar to these cases. Physicians should consider undiagnosed pheochromocytoma in patients who have adrenal tumors with a relatively high HU on CT and/or who develop DKA while taking SGLT2 inhibitors.
