A 28-year-old man with MEN 2A syndrome undergoes adrenalectomy for a catecholamine-secreting tumour. The resected specimen is bisected and shows a well-circumscribed mass displacing the adrenal cortex. The cut surface marked **A** exhibits a striking variegated appearance with red-brown haemorrhagic foci, areas of yellow necrosis, and pale tan viable tumour tissue. What pathological process is primarily responsible for the heterogeneous appearance of the cut surface marked **A**?
A. Caseous necrosis and calcification from chronic inflammatory infiltration by lymphocytes and macrophages
B. Cystic degeneration and liquefactive necrosis secondary to chronic hypoxia from tumour outgrowth exceeding blood supply
C. Repeated episodes of intratumoural haemorrhage and ischaemic necrosis due to rapid catecholamine release causing intense vasoconstriction followed by vasodilation
D. Coagulative necrosis from direct invasion of the tumour into adjacent renal vasculature
Explanation
Why "Repeated episodes of intratumoural haemorrhage and ischaemic necrosis due to rapid catecholamine release causing intense vasoconstriction followed by vasodilation" is right
The variegated haemorrhagic and necrotic cut surface (marked A) is a hallmark pathological feature of pheochromocytoma. The tumour's autonomous and episodic secretion of catecholamines (noradrenaline and adrenaline) causes intense, uncontrolled vasoconstriction followed by reactive vasodilation within the tumour vasculature. This cyclic vascular instability leads to repeated intratumoural haemorrhage and focal ischaemic necrosis, creating the characteristic variegated appearance with red-brown haemorrhagic zones, pale tan viable tumour, and yellow necrotic areas. This pattern is pathognomonic for pheochromocytoma and reflects the tumour's functional biology—the very catecholamine excess that causes the patient's hypertensive crisis and paroxysmal symptoms also damages the tumour's own vasculature. (Robbins and Cotran Pathologic Basis of Disease, 10th ed., Ch. Adrenal Glands)
Why each distractor is wrong
Cystic degeneration and liquefactive necrosis secondary to chronic hypoxia from tumour outgrowth exceeding blood supply: While hypoxia may contribute to some necrosis, the variegated pattern with active haemorrhage is not explained by simple outgrowth of blood supply. The episodic catecholamine-driven vascular instability is the primary driver, not passive ischaemia from size alone.
Coagulative necrosis from direct invasion of the tumour into adjacent renal vasculature: There is no evidence of renal vascular invasion in this case. The variegated appearance is intratumoural, not secondary to invasion of adjacent structures. Coagulative necrosis would produce a more uniform pale appearance, not the striking variegation seen here.
Caseous necrosis and calcification from chronic inflammatory infiltration by lymphocytes and macrophages: Caseous necrosis is characteristic of tuberculosis and granulomatous diseases, not pheochromocytoma. The histology described shows Zellballen pattern with sustentacular cells, not granulomatous inflammation. Calcification is not a prominent feature of the acute variegated appearance.
High-YieldNEET PG
The variegated haemorrhagic and necrotic cut surface of pheochromocytoma is a direct consequence of the tumour's own catecholamine excess causing cyclic intratumoural vasoconstriction and vasodilation—the tumour damages itself through its functional product.
Robbins and Cotran Pathologic Basis of Disease, 10th ed., Ch. Adrenal Glands
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