A 45-year-old woman has a medullary thyroid carcinoma. Serum calcitonin is markedly elevated. Which tumor marker should also be measured to screen for concurrent pheochromocytoma in a possible MEN2A syndrome?

• A AFP and beta-hCG
• B CEA and CA 19-9
• C NSE and S-100 protein
• D Chromogranin A and 24-hour urine catecholamines/metanephrines ✓

Explanation

MEN2A includes medullary thyroid carcinoma, pheochromocytoma, and primary hyperparathyroidism (RET proto-oncogene mutation). Pheochromocytoma is best screened with plasma free metanephrines or 24-hour urine fractionated metanephrines/catecholamines; chromogranin A is a general neuroendocrine marker that also supports the diagnosis. AFP/hCG are germ cell markers and are irrelevant here.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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