WBR0446

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Author [[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Will Gibson) (Reviewed by Alison Leibowitz) (Reviewed by Serge Korjian)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Pathology
Sub Category SubCategory::Endocrine
Prompt [[Prompt::A 45-year-old woman presents to the physician’s office with complaints of severe diarrhea of several days duration. The patient’s medical history is significant for recurrent kidney stones and a parathyroidectomy 8 years ago. Her fasting gastrin level is elevated and endoscopy reveals multiple ulcers in the stomach, duodenum, and jejunum. Which of the following findings is most frequently associated with this patient's condition?]]
Answer A AnswerA::Oral ganglioneuroma
Answer A Explanation AnswerAExp::Oral ganglioneuromatosis frequently occurs in patients with MEN2B syndrome.
Answer B AnswerB::Pheochromocytoma
Answer B Explanation AnswerBExp::Pheochromocytoma frequently occurs in MEN 2A and MEN 2B syndromes.
Answer C AnswerC::Medullary thyroid cancer
Answer C Explanation AnswerCExp::Medullary thyroid cancer frequently occurs in MEN 2A and MEN 2B syndromes.
Answer D AnswerD::Prolactinoma
Answer D Explanation AnswerDExp::Prolactinoma, a pituitary tumor, frequently occurs in MEN I syndrome.
Answer E AnswerE::Carcinoid tumor
Answer E Explanation AnswerEExp::Carcinoid tumor is an endocrine tumor, but is not frequently associated with MEN syndrome.
Right Answer RightAnswer::D
Explanation [[Explanation::The patient in this vignette most likely has multiple endocrine neoplasia type I (MEN 1). From the patient's past history of parathyroidectomy, it is highly likely that she had a parathyroid adenoma. Parathyroid adenomas classically secrete excessive PTH leading to elevated serum calcium and decreased serum phosphate levels. The increased serum calcium also leads to excess urinary excretion, increasing the risk of calcium oxalate kidney stones.

The current presentation is highly consistent with a gastrinoma, a gastrin-secreting tumor that arises from tissues of either the pancreas or the duodenal wall. Gastrin is a peptide hormone that stimulates parietal cells to increase gastric acid secretion. Patients with gastrinomas therefore frequently develop multiple ulcers due to excessive gastric acid production in the stomach. Nearly 25% of gastrinoma patients have MEN 1. A patient who has developed both parathyroid adenoma and gastrinoma is highly likely to be affected by MEN 1. MEN I syndrome is characterized by parathyroid tumors, pituitary tumors, and pancreatic endocrine tumors. Several subtypes of pancreatic endocrine tumors are associated with MEN 1, including gastrinoma, insulinoma, VIPoma, or glucagonoma. All of the MEN syndromes are dominantly inherited genetic disorders. MEN1 syndrome is caused by mutations in the MEN1 gene that ecodes the tumor suppressor menin.

A good way to remember which organ systems are affected by the different MEN syndromes is: MEN I (3 Ps) - Pituitary, Parathyroid, Pancreatic MEN IIa (1M,2Ps) - Medullary Thyroid Ca, Pheochromocytoma, Parathyroid MEN IIb (2Ms,1P) - Medullary Thyroid Ca, Marfanoid habitus/mucosal neuroma, Pheochromocytoma
Educational Objective: MEN I syndrome often manifests with pituitary tumors, parathyroid tumors, or pancreatic endocrine tumors.
References: Thakker, R. V., Newey, P. J., Walls, G. V., Bilezikian, J., Dralle, H., Ebeling, P. R., ... & Brandi, M. L. (2012). Clinical practice guidelines for multiple endocrine neoplasia type 1 (MEN1). The Journal of Clinical Endocrinology & Metabolism, 97(9), 2990-3011.
Basuroy R, Srirajaskanthan R, Prachalias A, Quaglia A, Ramage JK. Review article: the investigation and management of gastric neuroendocrine tumours. Aliment Pharmacol Ther. May 2014;39(10):1071-84.
First Aid 2014 page 329
First Aid 2015 page 337]]

Approved Approved::Yes
Keyword WBRKeyword::Prolactinoma, WBRKeyword::Pheochromocytoma, WBRKeyword::Gastrinoma, WBRKeyword::Neoplasia, WBRKeyword::MEN I, WBRKeyword::Cancer, WBRKeyword::Wermer syndrome, WBRKeyword::Diarrhea, WBRKeyword::Ulcers, WBRKeyword::Gastrinoma, WBRKeyword::Tumor, WBRKeyword::Pancreatic cancer, WBRKeyword::Multiple endocrine neoplasia
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