This 16-year-old boy presented with acute retrosternal pain possibly representing acute myocardial infarction. Cardiac enzymes were within reference ranges. There were marked increases in metanephrine to 3299 μg/24 h (reference, <400 μg/24 h), normetanephrine to 1309 μg/24 h (reference, 0–390 μg/24 h), and chromogranin A to 1605 ng/mL (reference, 0–150 μg/24 h). An incidental left adrenal mass was found during CTPA performed to exclude pulmonary embolism. 123I-MIBG scintigraphy was negative, and genetic screening detected SDHB (succinate dehydrogenase syndrome subunit B) gene mutation. Based on the gene mutation, 18F-DOPA PET/CT was performed, confirming a left-sided pheochromocytoma.