SAT-503 - A Diagnostic Enigma Unraveled: A Rare Case of Syndromic Bilateral Pheochromocytomas in Multiple Endocrine Neoplasia Type 2A

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant syndrome caused by germline mutations in the RET protooncogene on chromosome 10q11.21. MEN2A is characterized by medullary thyroid carcinoma (MTC), pheochromocytoma, and primary hyperparathyroidism. Pheochromocytomas occur in approximately 50% of MEN2A patients, with penetrance varying by specific RET mutations.

We report a case of a 33-year-old male with hypertension, postsurgical hypothyroidism status post total thyroidectomy at 1 year of age for thyroid cancer, Hirschsprung disease, and multiple prior abdominal surgeries, who presented with acute abdominal pain and hypertensive urgency. The patient was unable to provide reliable familial information due to low medical literacy. Bilateral adrenal masses were incidentally identified months earlier during ventral hernia evaluation.

Biochemical evaluation demonstrated abnormal dexamethasone suppression testing with cortisol 13.4 µg/dL (4.8–19.2) and dexamethasone 312 ng/dL (>200), suppressed ACTH 6 pg/mL (6–50), DHEA-S 64 µg/dL (57–522), aldosterone < 5 ng/dL ( < 28) with renin 3.39 ng/mL/hr (0.25–5.8), and profound hypothyroidism with TSH 700 µIU/mL (0.4–4.5), free T4 0.17 ng/dL (0.8–1.7), and total T3 < 20 ng/dL (80–200). Parathyroid hormone (PTH) was elevated at 84 pg/mL (15–65) with serum calcium 11.0 mg/dL (8.6–10.2). Tumor markers demonstrated elevated calcitonin 100 pg/mL ( < 10) and elevated CEA 13 ng/mL (≤3.4). Serial imaging demonstrated progressive bilateral heterogeneous adrenal mass enlargement. The right adrenal mass increased from 2.6 cm to 5.7 cm and measured 41 Hounsfield units on contrast-enhanced CT, while the left adrenal mass increased from 1.0 cm to 2.3 cm. Ga-68 DOTATATE PET-CT demonstrated avid bilateral adrenal uptake consistent with pheochromocytomas. Germline RET genetic testing is pending.

The patient was treated with intravenous levothyroxine, initiated on alpha-adrenergic blockade with doxazosin, and started on cinacalcet. Planned surgical management includes open right adrenalectomy with left cortical-sparing adrenalectomy.

Bilateral pheochromocytomas occur in up to 72% of MEN2A patients who develop pheochromocytoma, particularly among RET codon 634 carriers. These tumors present earlier than sporadic cases and are frequently asymptomatic but confer significant cardiovascular risk. Total adrenalectomy eliminates recurrence but causes lifelong adrenal insufficiency. Cortical-sparing adrenalectomy may preserve function, though recurrence rates approach 30% versus 3% after total adrenalectomy, with only ~50% avoiding chronic steroid dependency. Current evidence favors total adrenalectomy, reserving cortical-sparing approaches for select cases at experienced centers.

This case highlights diagnostic complexity and surgical risk in MEN2A-associated bilateral adrenal disease.

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