FRI219 Pheochromocytoma Presenting As A Case Of Worsening Diabetes Mellitus

Disclosure: J. Eapen: None. E. Sedlis Singer: None. T.X. Lu: None. J.N. Shapiro: None. Introduction: Pheochromocytoma is often diagnosed incidentally during unrelated abdominal imaging, in patients with a family history of known disease, or in patients presenting with the classic triad of symptoms: episodic headache, sweating, and tachycardia. We describe an atypical case of pheochromocytoma presenting as acute decompensation of DM. Case presentation: A 79 year old female with DM previously well-controlled on glimepiride for 4 years presented with an acute worsening of symptoms notable for abdominal fullness, weakness and weight loss. Laboratory results revealed an increase in HbA1c from 6% to 14% (nl <5.7%) since 3 months prior. Metformin and basal insulin were added to her regimen with a subsequent improvement in HbA1c. An abdominal CT scan was done given the acuity of progression in her DM, which revealed a 5.8cm adrenal mass. The patient denied easy bruising, striae, mood changes, dizziness, or hypertension. Biochemical evaluation demonstrated normal potassium level 3.7 (3.5-5.3 mmol/dL) and aldosterone 8ng/mL (<28), non-suppressed cortisol 7.8mcg/dL after dexamethasone 1mg given the night prior, but Cushing’s Disease was ruled out by normal salivary cortisol 0.08 mcg/dL (nl 0.04-0.56 mcg/dL) and urine free cortisol 22.8 mcg/ 24h (nl 4-50 mcg/24h), and further testing revealed elevated metanephrines and catecholamines during 24 hour urine collection, Epinephrine 129 mcg/24h (nl 2-24 mcg/24h), Metanephrine 7121 mcg/24h (nl 90-315 mcg/24h) and Normetanephrine 2078 mcg/ 24h (nl 122-676 mcg/24h).Repeat CT scan again showed an indeterminate 5.4 x 3.8 x 5.5 cm right adrenal mass, a 6.9mm lipid-rich left adrenal adenoma, and left adrenal gland hyperplasia. Consequently, the patient underwent laparoscopic right adrenalectomy with pathology revealing a diagnosis of pheochromocytoma. Post-op plasma fractionated metanephrines normalized and have remained normal. Immediately post-op, all diabetes medications (including insulin, glimepiride, and metformin) were stopped and she has had resolution of diabetes with HbA1c 6 on no medications when 1-year post-op. Discussion: Excess catecholamines are known to cause disruption of glucose and insulin homeostasis from desensitization of the beta-adrenergic receptor and increased insulin resistance(1). Despite this, less than a handful of pheochromocytoma cases have been reported to be presenting as an acute glycemic derangement as in our patient. References: 1. Ronen JA, Gavin M, Ruppert MD, Peiris AN. Glycemic Disturbances in Pheochromocytoma and Paraganglioma. Cureus. 2019 Apr 27;11(4):e4551.doi: 10.7759/cureus.4551. PMID: 31275775; PMCID: PMC6592834. Presentation: Friday, June 16, 2023