A 25-year-old man develops paroxysmal hypertension, diaphoresis, and palpitations. 24-hour urine shows markedly elevated catecholamines and metanephrines. Imaging reveals a 4 cm adrenal mass. This tumor arises from which cell type?

• A Adrenocortical cells of the zona fasciculata
• B Sustentacular (Schwann) cells of the adrenal medulla
• C Juxtaglomerular cells of the kidney
• D Chromaffin cells of the adrenal medulla (neural crest-derived) ✓

Explanation

Pheochromocytoma arises from chromaffin cells of the adrenal medulla (and extra-adrenal paragangliomas from paraganglia), which are neural crest-derived cells that synthesize and secrete catecholamines (epinephrine, norepinephrine, dopamine). The 'rule of 10s' applies: ~10% bilateral, 10% extra-adrenal, 10% malignant, 10% familial. Sustentacular cells are supportive stromal cells within the tumor (S100+). Cortical tumors cause hyperaldosteronism or Cushing syndrome; juxtaglomerular cells produce renin.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.