USMLE (United States Medical Licensing Examination) Step 1 Practice Exam 2026 - Free USMLE Step 1 Practice Questions and Study Guide

The tumor that is often benign and unilateral, presenting with symptoms such as palpitations, paroxysmal hypertension, anxiety, and drenching sweats, is known as a pheochromocytoma. This type of tumor arises from the adrenal medulla and is characterized by the excessive production of catecholamines, which are hormones like epinephrine and norepinephrine.

The symptoms associated with pheochromocytoma stem from catecholamine release into the bloodstream. The excess catecholamines lead to episodic hypertension, which can cause paroxysmal episodes of high blood pressure. Patients often report experiencing palpitations due to increased heart rate, feelings of anxiety or panic attacks, and drenching sweats associated with the adrenergic surge. These symptoms can occur spontaneously or be triggered by certain activities or stresses.

Pheochromocytomas are typically diagnosed through biochemical testing, which reveals elevated levels of plasma-free metanephrines or urinary catecholamines. The tumor is typically unilateral; however, bilateral pheochromocytomas can occur in the context of hereditary syndromes.

In contrast, the other choices represent different clinical conditions. Ectopic Cushing syndrome is characterized by excess cortisol production due to an ectopic secretion of