Adrenal Gland Disorders Practice Test 2026 – Comprehensive Exam Prep

Pheochromocytoma typically appears very bright on T2-weighted MRI because the tumor is highly vascular and water-rich, giving a characteristic hyperintense signal described as a "light-bulb" appearance. This prominent T2 brightness helps distinguish it from other adrenal lesions that may be less bright on T2 or show different post-contrast patterns. While ring-enhancing patterns and calcifications can occur in other processes or with different imaging sequences, they do not define the T2-weighted signature of pheochromocytoma. So, the bright T2 signal—the light-bulb sign—is the best clue on T2-weighted imaging.