Pituitary Pathology 2025 PDF

pituitary40X The Endocrine System Pituitary Pathology Jin Guo, MD 2025  The Endocrine System Objectives: At the end of this lecture the student will be able to name and discuss the main clinicopatholog...

pituitary40X The Endocrine System Pituitary Pathology Jin Guo, MD 2025  The Endocrine System Objectives: At the end of this lecture the student will be able to name and discuss the main clinicopathologic features of common lesions: – Pituitary gland – Thyroid gland – Parathyroid glands – Adrenal glands – Neuroendocrine system – Diabetes mellitus FNA cytology - “Salt and pepper” Histology  The Endocrine System Endocrine organs dedicated to production of hormones, e.g. pituitary, thyroid --- Endocrine components in organs having mixed functions, e.g. pancreas, ovary, testes --- Diffuse endocrine system - paracrine  Endocrine pathology Overproduction of hormone - hyperfunction Underproduction - hypofunction Mass effects - tumors  Posterior pituitary – Neurohypophysis – Oxytocin – ADH Pituitary Gland Pathology - Objectives Clinicopathologic and diagnostic morphologic features of common lesions: – Hyperpituitarism – Hypopituitarism – Mass effect Symptoms of hormone produced Hypopituitarism Local mass effects – Radiological changes – Visual field abnormalities – Elevated intracranial pressure  Hyperpituitarism In most cases, hyperpituitarism is due to adenoma arising in the anterior lobe. Less common causes: – Hyperplasia – Carcinoma – Ectopic hormone production – Some hypothalamic disorders  Pituitary Adenoma 10% of all intracranial neoplasm 25% incidental 3% occur with MEN syndrome 30-50 y/o Primary pituitary adenomas usually benign May or may not be functional More than 1 hormone may be produced by same cell Normal Adenoma IHC GH PRL  Morphology of pituitary adenomas Well circumscribed Size 1 cm or more, specially in nonfunctioning tumor Hemorrhage and necrosis seen in large tumors Microscopic features: – Uniform cells, one cell type (monomorphism) – Absent reticulin network – Rare or absent mitosis Uniform cells - pituitary adenoma  Prolactinoma 30% Functional even if small, but related to size Other causes of increased prolactin: estrogen therapy, pregnancy, hypothyroidism – Any mass in the suprasellar region may interfere with normal prolactin inhibition - increased prolactin (stalk effect) >200ng/ml - prolactinoma 30-200ng/ml - other causes Galactorrhea, amenorrhea, decrease libido and infertility  Growth hormone secreting adenoma 40% with GNAS1 gene mutation Persistent secretion of GH – increased insulin- like GF – symptoms May be mixed with prolactin secretion Symptoms delayed so adenomas are usually large Gigantism or Acromegaly Other symptoms: diabetes, arthritis, osteoporosis, increased BP ---  http://www.ghorayeb.com/files/pituitarylabelled2 Nelson Syndrome Rapid enlargement of a pituitary adenoma following bilateral adenalectomy Lack of negative feedback from corticol mass effect increased ACTH increased MSH Case 63 y/o man with acute hypotension developed during CABP. On awakening, he reported severe headache, lightheadedness, ptosis and visual field defects., – free thyroxine, 0.7 μg/L (0.9 to 1.8) – testosterone, 35 ng/L (241 to 827) – LH, 0.8 IU/L (2.4 to 15.9) – FSH, 1.1 IU/L (1 to 14) – prolactin, 0.6 μg/L (2.8 to 29.9) – cortisol, 1.0 μg/L (5 to 25)  Pituitary Apoplexy Usually non-functioning adenoma Usually large 80% of cases the tumor not yet diagnosed Intrasellar hemorrhage due to vascular erosion Sudden headache, visual field defect or double vision, acute hormonal insufficiency  Sellar mass – Tumors Adenohypophysial origin – Pituitary adenoma (macro and micro) – Pituitary carcinoma Neurohypophysial origin – Granular cell tumor Nonpituitary origin – Meningioma, Glioma, Craniopharyngioma, Germ cell tumor – Metastatic: carcinoma, lymphoma – Non tumor Cysts and Hamartomas Inflammatory Vascular: aneurysm  Craniopharyngioma 1-5 % of intracranial neoplasms Derived from remnants of Rathke’s pouch Suprasellar or intrasellar, often cystic with oily viscous fluid and calcification Children or adolescents, second peak >65 y/o. Symptoms may be delayed >20 yrs (50%) Symptoms of hypofunction or hyperfucntion of pituitary and or visual disturbances, diabetes insipidus Benign and slow growing  Hypopituitatism Loss of >75% of ant. pituitary Congenital or acquired Symptoms include dwarfism and effect of individual hormone deficiencies. Loss of MSH - decreased pigmentation  Hypopituitatism Acquired causes include: – Nonsecretory pituitary adenoma – Ischemic necrosis Sheehan’s syndrome (post partum hmg.) sickle cell anemia, DIC, pituitary apoplexy – Empty sella syndrome: May be primary due to downward bulge of arachnoid into sella floor, compressing pituitary Secondary is usually surgical – Iatrogenic by radiation or surgery – Autoimmune (lymphocytic) hypophysitis – Inflammatory - sarcoidosis or TB – Craniopharyngioma Case 40 y/o F, with postpartum hemorrhage. Undetectable BP, HR 120, cold extremities, pale conjunctivae, Hb 5g/dl Immediate care with vascular expansion with colloids, followed by a transfusion of 5 units of red cells Lactational failure and hypoglycemia, prolonged amenorrhea, fatigue and apathy--- http://synapse.koreamed.org/ArticleImage/0032JKNS/jkns-45-118-g005-l.jpg Acute infarct and necrosis Sheehan's syndrome - postpartum hypopituitarism -amenorrhea, failure to lactate, atrophy of breast, lack of pubic & axillary hair  Posterior pituitary syndromes Diabetes insipidus - ADH deficiency – Excessive urination, dilute urine, due to inability to reabsorb water from the collecting tubules. – Causes include head trauma, tumors and inflammations in pituitary or hypothalamus Syndrome of inappropriate ADH secretion – Causes excessive resorption of water – hyponatremia – Often caused by small cell ca of lung Other causes: non-neoplastic diseases of the lung (e.g., tuberculosis, pneumonia); Central nervous system disorders (e.g., meningitis, abscess, head trauma); Injury to the hypothalamus or posterior pituitary gland.  Summary Hyperpituitarism and adenoma Hypopituitarism Mass The normal microscopic appearance of the pituitary gland. reticulin Somatotrophs adenoma 'Stalk Effect'. Mass effect from nonsecreting pituitary adenoma Apoplexy craniopharyngioma