Neoplasms of Pituitary, Adrenal & Pancreas — Study Notes Summary & Study Notes

📝 Source summary and user request

Context: The user asked to create Anki decks based on the provided lecture material. These study notes synthesize the content to serve as a basis for creating spaced-repetition cards.

How to use these notes for Anki: Use each bolded heading and each concise clinical feature as a separate card: one side = condition or term, other side = defining features/diagnostic points/management clues. Prioritize high-yield clinical signs (e.g., acromegaly features, Cushing vs. Conn distinctions, pheochromocytoma triad) and diagnostic tests (dexamethasone suppression, urinary VMA, 24-hr urine free cortisol).

✅ Quick reminder for card creation

• Make separate cards for: pituitary adenoma types, GH excess (gigantism vs acromegaly), ACTH-producing adenoma (Cushing disease), Sheehan’s syndrome, Craniopharyngioma features, Chordoma features, Cushing’s (ACTH-dependent vs independent), Conn’s syndrome, Addison’s disease vs Waterhouse-Friderichsen, pheochromocytoma diagnosis, PanNET syndromes (insulinoma, gastrinoma, VIPoma), and MEN types I/II/III.

Note: These notes are designed to be converted into Anki cards; ensure clinical vignettes and diagnostic algorithms are included as separate cards for maximal clinical retention.

🧠 Pituitary — anatomy & physiology

Pituitary structure: The pituitary has an anterior (adenohypophysis) derived from Rathke’s pouch and a posterior (neurohypophysis) derived from the floor of the third ventricle. The anterior contains acidophils (GH, PRL), basophils (ACTH, TSH, FSH, LH) and chromophobes. Hypothalamic releasing/inhibiting factors control most anterior hormones; prolactin is mainly under dopamine-mediated inhibition.

🦠 Pituitary neoplasms — overview

Common lesions: Pituitary adenoma (most common), meningioma, craniopharyngioma, neurilemoma, paraganglioma, gangliocytoma, hemangioma. Malignant lesions include chordoma, germ cell tumors, hemangiopericytoma, metastases.

Clinical consequences: Hormonal hypersecretion (hyperpituitarism) or deficiency (hypopituitarism), and local mass effect (optic chiasm compression → bitemporal hemianopia, increased ICP → headache, nausea, vomiting).

🔬 Pituitary adenoma — types & features

General: >95% benign. Can be functional (hormone-producing) or nonfunctional. Functional tumors cause syndrome-specific features.

• Prolactinoma (most common): hyperprolactinemia → galactorrhea, amenorrhea, infertility in women; decreased libido/impotence in men. Often small microadenomas but symptomatic due to hormone.
• GH-producing (acidophilic): Gigantism if before epiphyseal closure; acromegaly in adults. Features: frontal bossing, prognathism, large hands/feet, cardiomegaly, insulin resistance, arthropathy.
• ACTH-producing (basophilic): Cushing disease (pituitary source). Features: moon facies, central obesity, hypertension, osteoporosis, hyperglycemia, skin changes.
• Chromophobe / null-cell adenomas: Often nonfunctional, present with mass effect. Some chromophobes may secrete prolactin.

Microadenoma vs macroadenoma: Microadenoma <10 mm (often hormonal), macroadenoma larger and more likely to cause mass effect.

🩺 Hypopituitarism & syndromes

Causes: non-secretory adenoma, Sheehan’s syndrome (postpartum ischemic necrosis), surgery, radiation, trauma, metastases, granulomatous infection (TB, sarcoid).

Sheehan’s syndrome: postpartum hypotension → pituitary ischemic necrosis → failure of lactation (low PRL), loss of gonadal/thyroid/adrenal axis function.

Empty sella syndrome: CSF herniation compresses pituitary causing variable hypopituitarism.

🧩 Suprasellar tumors

Craniopharyngioma: Rathke’s pouch remnants. Occurs in children/young adults. Mixed solid + cystic, “machine oil” cyst contents, peripheral palisading epithelium, causes visual disturbance, hypopituitarism, diabetes insipidus.

Chordoma: Notocord origin, midline skull base or sacrum, physaliphorous cells with mucin; may erode sella and damage pituitary.

🟨 Adrenal cortex — zones & hormones

Zones: Zona glomerulosa (ZG) → mineralocorticoids (aldosterone); Zona fasciculata (ZF) → glucocorticoids (cortisol); Zona reticularis (ZR) → sex steroids.

⚖️ Adrenal hyperfunction (hyperadrenalism)

Syndromes:

• Cushing’s syndrome = hypercortisolism. Causes: ACTH-dependent (pituitary adenoma = Cushing disease; ectopic ACTH) and ACTH-independent (adrenal adenoma/carcinoma, exogenous steroids).
• Conn’s syndrome (primary hyperaldosteronism): aldosterone-secreting adenoma → hypertension, hypokalemia, metabolic alkalosis.
• Adrenogenital syndrome (congenital adrenal hyperplasia): enzyme defects (eg, 21-hydroxylase deficiency) → decreased cortisol/aldosterone, increased ACTH, adrenal hyperplasia, excess androgens → virilization.

Diagnosis of Cushing’s: elevated serum cortisol, increased 24‑hr urine free cortisol, loss of diurnal rhythm, plasma ACTH measurement, dexamethasone suppression testing to distinguish pituitary vs ectopic vs adrenal causes.

🧾 Corticotroph pathology

Pituitary Cushing (Cushing disease): ACTH-producing pituitary microadenomas. Pituitary Crooke hyaline change occurs in remaining corticotrophs. Nelson’s syndrome: rapid corticotroph tumor growth and hyperpigmentation after bilateral adrenalectomy for Cushing’s.

🧪 Lab patterns for Cushing’s workup

• Pituitary Cushing: high ACTH, not suppressed by low-dose dexamethasone, suppressed by high-dose dexamethasone.
• Ectopic ACTH: high ACTH, not suppressed by low- or high-dose dexamethasone.
• Adrenal tumor: low ACTH due to negative feedback; dexamethasone does not suppress cortisol.

🧾 Adrenal tumors: adenoma vs carcinoma

Adenoma: small, encapsulated, resembles normal cortex, minimal mitoses, no vascular invasion. Carcinoma: large, nonencapsulated, hemorrhage/necrosis, pleomorphism, frequent mitoses, vascular invasion and metastasis; poorer prognosis.

🛑 Hypoadrenalism (adrenal insufficiency)

Acute: Waterhouse‑Friderichsen syndrome (meningococcal endotoxin-induced hemorrhagic adrenal necrosis) → shock, DIC, bilateral adrenal hemorrhage.

Chronic (Addison’s disease): most commonly autoimmune; also TB, metastases, amyloidosis. Features: weakness, weight loss, hyperpigmentation (if primary), hypotension, hyponatremia, hyperkalemia.

🧬 Adrenal medulla & pheochromocytoma

Pheochromocytoma: tumor of chromaffin cells → excess catecholamines (E/NE) → paroxysmal hypertension, headaches, sweating, tachycardia. Diagnosis: elevated urinary VMA (vanillylmandelic acid) or plasma/urine catecholamines, imaging (CT/MIBG). Associations: MEN II, von Hippel‑Lindau, NF1.

🩺 Pancreatic neuroendocrine tumors (PanNETs)

Overview: Islet cell neoplasms (insulinoma, gastrinoma, glucagonoma, VIPoma, somatostatinoma). Rare. Can be sporadic or part of MEN1.

• Insulinoma: most common PanNET. Small, solitary; causes episodic hypoglycemia. Histology often shows amyloid deposition.
• Gastrinoma (Zollinger–Ellison): gastric acid hypersecretion → refractory peptic ulcer disease; frequently malignant and metastatic at diagnosis.
• VIPoma: watery diarrhea, hypokalemia, achlorhydria (WDHA syndrome).

🧬 Molecular & MEN syndromes

PanNET pathogenesis: mutations in MEN1, loss-of-function in PTEN/TSC2, ATRX/DAXX dysfunction.

MEN syndromes:

• MEN1 (Wermer): pituitary adenomas, parathyroid hyperplasia/adenomas, pancreatic tumors. MEN1 gene (menin) mutation.
• MEN2A (Sipple): medullary thyroid carcinoma, pheochromocytoma, parathyroid hyperplasia.
• MEN2B (MEN IIB/III): medullary thyroid carcinoma, pheochromocytoma, mucosal neuromas, marfanoid habitus. RET proto-oncogene gain-of-function mutation.

🧾 Clinical pearls & high-yield distinctions

• Cushing disease = pituitary ACTH source; Cushing syndrome = clinical hypercortisolism from any cause.
• Nelson’s syndrome arises after bilateral adrenalectomy for Cushing’s disease.
• Conn’s syndrome → HTN + hypokalemia (primary hyperaldosteronism).
• Pheochromocytoma triad: headaches, sweating, tachycardia; measure urinary VMA.
• Insulinoma causes fasting hypoglycemia; amyloid often present in tumor stroma.

🔎 Diagnostic & histologic notes

Pituitary adenomas: monotonous endocrine cells, arranged in cords/nests; IHC and EM helpful for hormone identification. Craniopharyngioma: squamoid epithelium with peripheral palisading and cysts with oily fluid. Chordoma: physaliphorous cells in mucin, CK+/EMA+.

📚 Summary

Most endocrine neoplasms are adenomas and produce either hormone excess or mass effects. Distinguish functional from nonfunctional lesions, recognize key clinical syndromes (Cushing, Conn, Addison, pheochromocytoma, PanNET syndromes), and use hormone testing plus imaging and histology/IHC for diagnosis. These notes are optimized to be converted into focused Anki cards for stepwise learning.