Multiple Endocrine Neoplasia (MEN) Syndromes

MEN

3-P

2-P-1-M

1-P-2-M

Autosomal dominant neoplastic syndromes grouped by organs beginning with the letters P and M.

MEN syndromes are hereditary cancer predispositions caused by specific germline mutations: MEN1 (menin tumor suppressor gene, chromosome 11) vs MEN2A/2B (RET proto-oncogene gain-of-function, chromosome 10).

Systematic Breakdown

MEN 1

3 P's (Pituitary, Parathyroid, Pancreas)

Parathyroid adenomas (95%), Pancreatic neuroendocrine tumors (Gastrinoma, Insulinoma), Pituitary adenomas (Prolactinoma).

MEN 2A

2 P's, 1 M (Parathyroid, Pheo, Medullary)

Medullary thyroid carcinoma (100%), Pheochromocytoma (50%), Parathyroid hyperplasia (20-30%).

MEN 2B

1 P, 2 M's (Pheo, Medullary, Mucosal/Marfanoid)

Medullary thyroid carcinoma (aggressive in infancy), Pheochromocytoma, Mucosal neuromas (lips/tongue) & Marfanoid habitus (NO parathyroid involvement).

High-Yield Clinical Pearls & Exam Tips

Prophylactic thyroidectomy is indicated in children with RET mutations due to early, aggressive Medullary Thyroid Carcinoma.
In patients with pheochromocytoma and medullary thyroid cancer, ALWAYS resect the pheochromocytoma FIRST to prevent fatal intraoperative hypertensive crisis during neck surgery.

Related Pharmaceuticals

Phenoxybenzamine Octreotide Levothyroxine

Related Clinical Conditions

Medullary Thyroid Carcinoma Zollinger-Ellison Syndrome Pheochromocytoma

Authoritative Sources: Robbins & Cotran Pathologic Basis of Disease 10e · First Aid USMLE Step 1

Multiple Endocrine Neoplasia (MEN) Syndromes

Systematic Breakdown

3 P's (Pituitary, Parathyroid, Pancreas)

2 P's, 1 M (Parathyroid, Pheo, Medullary)

1 P, 2 M's (Pheo, Medullary, Mucosal/Marfanoid)

More Endocrinology Mnemonics

Cushing Syndrome Signs: CUSHING

Hypercalcemia Symptoms & Signs

Pheochromocytoma Clinical Features

System Notice

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