Multiple endocrine neoplasia: Pathology review


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Multiple endocrine neoplasia: Pathology review


Adrenal gland disorders

Congenital adrenal hyperplasia

Primary adrenal insufficiency

Waterhouse-Friderichsen syndrome


Adrenal cortical carcinoma

Cushing syndrome

Conn syndrome

Thyroid gland disorders

Thyroglossal duct cyst


Graves disease

Thyroid eye disease (NORD)

Toxic multinodular goiter

Thyroid storm


Euthyroid sick syndrome

Hashimoto thyroiditis

Subacute granulomatous thyroiditis

Riedel thyroiditis

Postpartum thyroiditis

Thyroid cancer

Parathyroid gland disorders





Pancreatic disorders

Diabetes mellitus

Diabetic retinopathy

Diabetic nephropathy

Pituitary gland disorders


Pituitary adenoma






Growth hormone deficiency

Pituitary apoplexy

Sheehan syndrome


Constitutional growth delay

Diabetes insipidus

Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

Gonadal dysfunction

Precocious puberty

Delayed puberty

Premature ovarian failure

Polycystic ovary syndrome

Androgen insensitivity syndrome

Kallmann syndrome

5-alpha-reductase deficiency

Polyglandular syndromes

Autoimmune polyglandular syndrome type 1 (NORD)

Endocrine tumors

Multiple endocrine neoplasia

Pancreatic neuroendocrine neoplasms

Zollinger-Ellison syndrome

Carcinoid syndrome



Opsoclonus myoclonus syndrome (NORD)

Endocrine system pathology review

Adrenal insufficiency: Pathology review

Adrenal masses: Pathology review

Hyperthyroidism: Pathology review

Hypothyroidism: Pathology review

Thyroid nodules and thyroid cancer: Pathology review

Parathyroid disorders and calcium imbalance: Pathology review

Diabetes mellitus: Pathology review

Cushing syndrome and Cushing disease: Pathology review

Pituitary tumors: Pathology review

Hypopituitarism: Pathology review

Diabetes insipidus and SIADH: Pathology review

Multiple endocrine neoplasia: Pathology review

Neuroendocrine tumors of the gastrointestinal system: Pathology review


Multiple endocrine neoplasia: Pathology review

USMLE® Step 1 questions

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USMLE® Step 1 style questions USMLE

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A 34-year-old woman comes to the office complaining of consistent diarrhea for the last 2 months. The patient has experienced watery, tea-colored diarrhea that happens even when she has not eaten anything. She denies any associated abdominal pain or difficulty swallowing. The patient feels fatigued and weak with muscle cramps which she attributes to being dehydrated. Medical history includes hyperparathyroidism and nephrolithiasis. The patient’s temperature is 37.0°C (98.6°F), pulse is 100/min, respirations are 20/min, and blood pressure is 100/60 mmHg. Physical examination shows dry mucous membranes and decreased skin turgor without abdominal tenderness. Laboratory tests show the following:  
Laboratory value  Result
 Sodium  144 mEq/L 
 Potassium   2.5 mEq/L 
 Chloride  93 mEq/L 
 Bicarbonate  21 mEq/L 
 Calcium   12 mg/dL 
 Glucose  250 mg/dL 
 Parathyroid hormone  350 pg/mL 

Which of the following is the most likely mechanism of this patient’s symptoms?


Content Reviewers

Yifan Xiao, MD


David G. Walker

Anca-Elena Stefan, MD

Rachel Yancey

Zachary Kevorkian, MSMI

Two individuals came in for genetic testing based on recommendations from their primary care physicians. The first one is 24 year old Kurt, who was previously diagnosed with Zollinger-Ellison syndrome and also has an adenoma in one of his parathyroid glands. On the clinical examination, doctors observed that he has gynecomastia. His mother also has parathyroid adenomas. The other one is 19 year old Courtney, who was previously diagnosed with parathyroid hyperplasia and pheochromocytoma. Her father has recently been diagnosed with thyroid medullary cancer.

Although their presentation and family history differ, both people have multiple endocrine neoplasias, or MEN for short. These are a group of inherited diseases which cause tumors to grow in the endocrine glands of the body. The endocrine glands affected in multiple endocrine neoplasia are the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, and the pancreas. So in multiple endocrine neoplasias, there are tumors that form in these glands that lead to overproduction of hormones.

Multiple endocrine neoplasias are caused by genetic mutations in one of two genes: either MEN1 or RET, which codes for receptor tyrosine kinase. For your exams, remember that both of these genes have a dominant inheritance pattern, so only one copy of the mutated gene is needed to get the disease.

Okay, let’s start with the MEN1 gene that is found on chromosome 11 and codes for a tumor suppressor protein called menin, which - under normal circumstances - stops a cell from dividing uncontrollably. MEN1 mutations cause MEN type 1. For your tests, you absolutely have to know that there are three types of tumors associated with MEN type 1: parathyroid, pancreatic, and pituitary.


  1. "Robbins Basic Pathology" Elsevier (2017)
  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Zollinger Ellison Syndrome in a Patient with Multiple Endocrine Neoplasia Type 1: A Classic Presentation" Case Reports in Gastrointestinal Medicine (2019)
  4. "Update on multiple endocrine neoplasia Type 1 and 2" La Presse Médicale (2018)
  5. "Multiple Endocrine Neoplasia" Surgical Oncology Clinics of North America (2015)
  6. "Williams Textbook of Endocrinology" Elsevier (2019)

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