A 32-year-old man has episodic hypertension, palpitations, and diaphoresis. 24-hour urine metanephrines are markedly elevated. Imaging reveals an adrenal mass. Histology cannot reliably distinguish benign from malignant pheochromocytoma. Which scoring system is used for risk stratification?
- A Gleason score for nuclear grade
- B Fuhrman grade for clear cell morphology
- C PASS (Pheochromocytoma of the Adrenal gland Scaled Score) — evaluates vascular invasion, capsular invasion, profound nuclear pleomorphism, mitoses, and other features to determine malignancy potential ✓
- D Nottingham grade for architectural and mitotic features
Explanation
In pheochromocytoma, the conventional histological criteria for malignancy cannot be applied (unlike most tumors), because cellular pleomorphism and mitoses can occur in benign cases. Malignancy is defined by metastasis to non-chromaffin tissue. The PASS (Pheochromocytoma of the Adrenal gland Scaled Score) evaluates 12 histological variables (large nests/diffuse growth, central necrosis, vascular invasion, capsular invasion, profound nuclear pleomorphism, hyperchromatism, abnormal mitoses, >3 mitoses/10 HPF, monotony, spindling) — a score ≥4 suggests malignant potential. PASS ≥4 correlates with clinically malignant behavior in follow-up.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.