[Rare cause of insufficient metabolic control of diabetes mellitus - Case 10/2011].

History And Admission Findings: A 48-year-old patient presented with an insufficient control of his diabetes mellitus which was known since 3 years. The antidiabetic medication comprised metformin and exenatide.

Investigations: Physical examination revealed, beside elevated blood pressure, abdominal purple striae. Endocrine testing was consistent with ectopic Cushing's syndrome. Abdominal CT showed a 5 cm measuring, inhomogeneous, contrast-enhanced mass in the right suprarenal area which was positive on iodine-131 MIBG SPECT. Furthermore, urinary catecholamines were markedly increased.

Diagnosis, Treatment And Course: Diagnosis of an ACTH-producing pheochromocytoma was made and an open adrenalectomy was performed. Histology confirmed a pheochromocytoma with potential aggressive clinical behaviour according to the Pheocromocytoma of the Adrenal gland Scaled Score. 6 months after the intervention, glucose control was significantly improved with an HbA1c of 5.5%.

Conclusions: An ACTH-producing pheochromocytoma is a very rare cause of deterioration of glucose control. However, in presence of typical clinical findings an endocrine work-up is warranted.