Ectopic ACTH-producing neuroendocrine tumor occurring with large recurrent metastatic pheochromocytoma: a case report

Pheochromocytoma With High Adrenocorticotropic Hormone Production Capacity Without Pigmentation and Cushingoid Symptoms: A Case Report With a Literature Review

Pheochromocytoma or paraganglioma (PPGL) originating from chromaffin cells can produce diverse hormones in addition to catecholamines, including adrenocorticotropic hormone (ACTH). In pheochromocytoma, high levels of ACTH might not result in pigmentation as typically observed in Addison's disease, and patients might not exhibit the symptoms of Cushing's syndrome, despite ACTH-dependent hypercortisolism. A 63-year-old male patient with hypertension was admitted to our facility, and computed tomography (CT) revealed a large right adrenal tumor. Despite high plasma ACTH (700-1300 pg/mL) and serum cortisol (90-100 µg/dL) levels, no physical pigmentation or Cushingoid symptoms were observed. Urinary metanephrine and normetanephrine levels reached as high as 16.0 mg and 3.2 mg, respectively. 123I-metaiodobenzylguanidine (MIBG) scintigraphy was negative. Low-dose dexamethasone paradoxically increased ACTH and cortisol levels, indicating the potential positive feedback regulation of both hormones by glucocorticoids. The patient was diagnosed with an ACTH-producing pheochromocytoma and underwent successful laparoscopic surgery to remove the adrenal tumor under the intravenous administration of a high-dose α-blocker and hydrocortisone. The levels of ACTH, cortisol, and urinary metanephrine/normetanephrine returned close to normal after tumor removal. We report a rare case of pheochromocytoma with extremely high ACTH/cortisol production but without pigmentation or Cushingoid symptoms. We also reviewed previous reports of ACTH-producing PPGL regarding the paradoxical regulation of ACTH/cortisol by glucocorticoids, pigmentation, Cushingoid symptoms, and negativity of 123I-MIBG scintigraphy.

METFORMIN-AND GLICLAZIDE-BASED DIABETES TREATMENT EXPERIENCE IN A PATIENT WITH GITELMAN SYNDROME

INTRODUCTION

Gitelman Syndrome (GS) is a genetic tubulopathy frequently linked with insulin resistance. The possibility of developing Diabetes Mellitus (DM) in GS increases with the causes of insulin resistance. Hypokalemia is one of the most common electrolyte disorders in GS, and most diabetic drugs can cause hypokalemia. Considering this dilemma, we presented a DM treatment experience in a GS case.

CASE PRESENTATION

A 47-year-old male GS patient with a potassium-rich diet complained of weight loss and dry mouth for 2-3 months. The laboratory tests revealed a higher HbA1c level, as high as 11.8%. The remaining abnormal laboratory test results (hypokalemia, hypomagnesemia, metabolic alkalosis) indicated a patient with GS. The patient was placed on a metformin+gliclazide-based treatment. Oral potassium and magnesium supplementation were started for the patient whose hypokalemia increased in the first control, and the potassium dose was doubled in the third control. In the first-month follow-up visit, it was observed that the blood potassium level was improved, and hyperglycemia was optimized.

CONCLUSION

In brief, any treatment for DM can be selected in GS patients with DM by performing frequent electrolyte monitoring. Like our case, oral potassium supplementation was adequate for the metformin + gliclazide combination-coincidence hypokalemia.