Phaeochromocytoma
MEN1 is characterized by tumors of the Parathyroid, Pancreas, and Pituitary, while MEN2A and MEN2B involve the Phaeochromocytoma and Medullary Thyroid Carcinoma with distinct additional features.
PHAEOCHROMOCYTOMA
- Definition: A catecholamine-secreting tumour of the adrenal medulla chromaffin cells.
- Rule of 10s: 10% bilateral, 10% malignant, 10% extra-adrenal, 10% familial (associated with MEN2, VHL, NF1).
- Clinical features (The 5 Ps): Palpitations, Perspiration, Pallor, Pain (headache), Pressure (hypertension, often paroxysmal).
- Diagnosis: 24-hour urinary catecholamines and metanephrines (gold standard). Plasma metanephrines are a sensitive screening test. CT or MRI of the adrenals. MIBG scan can confirm functional tissue and detect extra-adrenal lesions.
- Treatment: Alpha-blockade FIRST (e.g., phenoxybenzamine), followed by beta-blockade, and then surgery. Beta-blockers should never be administered first.
Read this in Endocrine & Renal Pathology — Must Know Notes
PHAEOCHROMOCYTOMA
- Definition: Catecholamine-secreting tumour of adrenal medulla chromaffin cells.
- Rule of 10s: 10% bilateral, 10% malignant, 10% extra-adrenal, 10% familial (MEN2, VHL, NF1).
- Clinical (5 Ps): Palpitations, Perspiration, Pallor, Pain (headache), Pressure (hypertension — paroxysmal).
- Diagnosis: 24h urinary catecholamines + metanephrines (gold standard). Plasma metanephrines (sensitive screening). CT/MRI adrenals. MIBG scan (confirms functional tissue, detects extra-adrenal disease).
- Treatment: Alpha-blockade FIRST (phenoxybenzamine) → then beta-blockade → then surgery. Never beta-block first — causes unopposed alpha → hypertensive crisis.
Read this in Endocrine & Renal Pathology
What our notes say
- MEN1 is characterized by tumors of the Parathyroid, Pancreas, and Pituitary, while MEN2A and MEN2B involve the Phaeochromocytoma and Medullary Thyroid Carcinoma with distinct additional features. (ADRENAL NEOPLASMS — Adenoma vs Carcinoma)
- Episodic headache, sweating and palpitations suggest phaeochromocytoma. (Endocrinology and Gastroenterology Question Bank: 12 Clinical MCQs)
- | Phaeochromocytoma | Episodes of sweating, headache, palpitations; urine or plasma metanephrines | (Hypertension)
- Phaeochromocytoma — excess catecholamines inhibit insulin secretion, stimulate glycogenolysis/gluconeogenesis (Medical MCQs: Chemical Pathology & Haematology Exam Review)
- Phaeochromocytoma — excess catecholamines inhibit insulin secretion and stimulate glycogenolysis/gluconeogenesis, raising blood glucose (Chemical Pathology Exam Paper: Acid-Base, Electrolytes, Diabetes & Renal Functio)
- Phaeochromocytoma — catecholamines → glycogenolysis + ↓insulin release (Renal, Liver, Cardiac & Adrenal Function Tests for Year 3)
Study material on Phaeochromocytoma
- ADRENAL NEOPLASMS — Adenoma vs Carcinoma
- ADRENAL NEOPLASMS — Adenoma vs Carcinoma
- ADRENAL NEOPLASMS — Adenoma vs Carcinoma
- Endocrine & Renal Pathology
- Renal, Liver, Cardiac & Adrenal Function Tests for Year 3