PHEOCHROMOCYTOMA Flashcards
What is the hallmark triad of clinical manifestations in pheochromocytoma?
A. Hypertension, nausea, and vomiting
B. Palpitation, headache, and profuse sweating
C. Fever, chest pain, and arrhythmia
D. Weakness, weight loss, and vision changes
Correct Answer: B. Palpitation, headache, and profuse sweating
Rationale: The classic triad of pheochromocytoma includes palpitation, headache, and profuse sweating. These symptoms are caused by episodic surges in catecholamine levels.
Which biochemical test is the most sensitive for diagnosing pheochromocytoma?
A. Urinary catecholamines
B. Plasma metanephrines
C. Serum cortisol levels
D. Urinary vanillylmandelic acid (VMA)
Correct Answer: B. Plasma metanephrines
Rationale: Plasma metanephrines are the most sensitive test for diagnosing pheochromocytoma and are less affected by stress-related false positives compared to urinary catecholamines.
What is the optimal imaging modality for detecting extra-adrenal pheochromocytomas and paragangliomas?
A. CT without contrast
B. T2-weighted MRI with gadolinium contrast
C. X-ray imaging
D. Ultrasound
Correct Answer: B. T2-weighted MRI with gadolinium contrast
Rationale: T2-weighted MRI with gadolinium contrast is better than CT for imaging extra-adrenal pheochromocytomas and paragangliomas due to its superior soft-tissue contrast resolution.
What is the first-line therapy for metastatic pheochromocytoma with scintigraphically documented metastases?
A. Averbuch’s chemotherapy protocol
B. Surgical tumor removal
C. Nuclear medicine therapy with 131I-MIBG
D. Stereotactic radiation
Correct Answer: C. Nuclear medicine therapy with 131I-MIBG
Rationale: For metastatic pheochromocytoma, nuclear medicine therapy with 131I-MIBG is the preferred first-line treatment, as it targets scintigraphically documented metastases effectively.
Which genetic syndrome is most commonly associated with pheochromocytoma?
A. MEN 1
B. MEN 2 (2A and 2B)
C. Von Hippel-Lindau syndrome
D. Li-Fraumeni syndrome
Correct Answer: B. MEN 2 (2A and 2B)
Rationale: Pheochromocytomas are a key component of MEN 2 (2A and 2B), an autosomal dominant syndrome caused by mutations in the RET proto-oncogene.
What is the recommended preoperative preparation for pheochromocytoma surgery?
A. Administering beta-blockers only
B. Ensuring blood pressure control with α-adrenergic blockers
C. Avoiding salt intake and hydration
D. Starting chemotherapy before surgery
Correct Answer: B. Ensuring blood pressure control with α-adrenergic blockers
Rationale: Preoperative preparation involves using α-adrenergic blockers (e.g., phenoxybenzamine) to achieve blood pressure control, along with liberal salt intake and hydration to prevent orthostasis during surgery.
Which histological pattern is characteristic of pheochromocytomas?
A. Papillary structures
B. Zellballen pattern
C. Granulomatous inflammation
D. Signet-ring cells
Correct Answer: B. Zellballen pattern
Rationale: Pheochromocytomas and paragangliomas display the characteristic Zellballen pattern, comprising nests of neuroendocrine chief cells surrounded by sustentacular cells.
What is the preferred surgical approach for removing most pheochromocytomas?
A. Open laparotomy
B. Laparoscopy or retroperitoneoscopy
C. Robotic surgery
D. Endovascular embolization
Correct Answer: B. Laparoscopy or retroperitoneoscopy
Rationale: Minimally invasive techniques, such as laparoscopy or retroperitoneoscopy, are the standard approaches for pheochromocytoma surgery, offering reduced recovery times and complications.
