SAT-487 Thirty Years To Diagnosis: A Case Of Pseudopheochromocytoma In A 70-year-old Female

Abstract

Pseudopheochromocytoma is a disorder characterized by intense paroxysmal hypertension and variably elevated catecholamine metabolite levels, but without a detectable pheochromocytoma or paraganglioma. Pseudopheochromocytoma clinically mimics pheochromocytoma but differs in etiology despite similar symptoms such as episodic hypertension, headache, and diaphoresis. While pheochromocytoma is a neuroendocrine tumor that secretes excess catecholamines, pseudopheochromocytoma is a syndrome often associated with a history of emotional stressors and is believed to stem from the dysregulation of the autonomic nervous system. We present the case of a 70-year-old female patient experiencing uncontrollable hypertensive crises requiring several ICU admissions and treatment with various antihypertensive medications for three decades. The patient was referred to Endocrine Oncology for evaluation of a possible pheochromocytoma due to her long-standing history of episodic hypertension and elevated catecholamine metabolites. Laboratory testing during a hypertensive episode revealed plasma free normetanephrine of 2.20 nmol/L (ref: <0.89 nmol/L) and urine normetanephrine of 1751 µg/24 h (ref: 95–650 µg/24 h), both exceeding twice the upper limit of normal. Urine metanephrine was elevated at 407 µg/24 h (ref: 36-229 µg/24 h). At presentation to Endocrine Oncology, the patient reported that hypertensive episodes began in her 40s, with a progressive escalation in frequency over time. She identified bloating as an early symptom, followed by vomiting, flushing, and headache, without preceding psychological distress. She reported paroxysms with systolic pressures reaching 220 mmHg, one resulting in a transient ischemic attack and another in pulmonary edema. Her medical history includes OSA managed with CPAP use and incidentally noted partial empty sella syndrome. Anatomic and functional imaging including CT scans of the abdomen and pelvis and a Cu-64 DOTATATE PET-CT excluded a diagnosis of pheochromocytoma or paraganglioma. Her history of significant personal and occupational emotional stressors raised the possibility of pseudopheochromocytoma. The patient was started on escitalopram and referred to psychiatry, after which, she experienced significantly fewer hypertensive episodes and a dramatic improvement in quality of life. The patient’s most recent labs revealed normal plasma normetanephrine at 50 pg/mL (ref: ≤148 pg/mL), metanephrine <25 pg/mL (ref: ≤57 pg/mL), and total metanephrines at 50 pg/mL (ref: ≤205 pg/mL). At her most recent follow-up, she reported only two hypertensive episodes in the past seven months, compared to occurrences every 1–2 weeks at the time of presentation. This case illustrates the diagnostic challenges of pseudopheochromocytoma and the importance of early intervention in preventing complications and improving health outcomes.