Pituitary Pathology Flashcards
How do the following signals from the hypothalamus affect the Pituitary gland?
- TRH
- Dopamine
- CRH
- GHRH
- Somatostatin
- GnRH
- TRH → TSH
- Dopamine (-) → Prolactin
- CRH → ACTH
- GHRH → GH
- Somatostatin (-) → GH
- GnRH → FSH/LH
What types of appearance/staining will be effective in the anterior pituitary?
Acidophilic, Basophilic, Chromophobic
Special immunostains used for specific hormones
What types of cells are found in the posterior pituitary; what is secreted?
Contains pituicytes and axons; secretes ADH and oxytocin
What are some differences in appearance between the anterior and posterior pituitary?
Anterior pituitary is more cellular and has small clusters of cells that are held together by reticulin
Pituitary adenomas
Gender preference:
Age:
Gender preference: Women > Men
Age: 3rd - 6th decades
What type of hormone secretion is most common in a pituitary adenoma? What types of cells are present? How are they stained?
Prolactin (approx. 30%) - Lactotrophs - Chromophobic staining
How are pituitary adenomas removed?
Trans-sphenoidal resection
How can a pituitary adenoma be distinguished from a normal pituitary?
Adenomas have destruction of normal patterns of reticulin and express only one cell type
What are some potential causes of a prolactin adenoma?
- Associated with medications that interfere with dopamine
- Stalk effect - other regional tumors may disturb the hypothalamic inhibition of prolactin secretion
- Pregnancy
What is Sheehan syndrome?
Postpartum ischemic necrosis of the pituitary gland - pituitary enlarges during pregnancy and is susceptible to ischemia
What are Rathke Cleft Cysts? How do they appear?
Cysts lined by ciliated cuboidal cells with scattered goblet cells and anterior pituitary cells - Remnant of rathke’s pouch
What is a craniopharyngioma and where can it be located?
A benign tumor usually located suprasellar
May also be within sella, third ventricle or (rarely) pineal region
Craniopharyngioma characteristics
- Age peaks:
- Presenting symptoms:
- Types (2):
- Age peaks: 5-14 y/o; 65-74 y/o
- Presenting symptoms: Visual abnormalities (chiasm) and hypopituitarism
- Types (2): Adamantinomatous type and Papillary type
What are appearances and characteristics of the adamantinomatous type of craniopharyngioma?
- Cysts filled with dark brown fluid and cholesterol crystals
- Basally palisading squamous epithelium
- Abdant keratin
- Local invasion of brain with chronic inflammation
What is the appearance of the papillary type of craniopharyngioma?
Papillary architecture with no keratin formation
Large pituitary adeonmas can cause bitemporal ___________
Hemianopsia (no vision in half of visual field)
The parathyroid develops from…
- Pharyngeal pouches
- Inferior portion & thymus - 3rd pouch
- Superior portion - 4th pouch
Describe the appearance of a normal parathyroid (color, cell type, distinguishing features)
- Yellow, brown ovoid nodule composed primarily of chief cells and oxyphil cells
- Large amount of intervening stromal fat in adults - adipocytes serve as a key distinguishing feature
Hormone secretions from the parathyroid are controlled by levels of…
free calcium
What types of disorders cause hyperfunctioning of the parathyroid? Hypofunctioning?
- Hyperfunction
- Parathyroid Hyperplasia
- Parathyroid Adenoma
- Parathyroid Carcinoma
- Hypofunction
- Congenital (DiGeorge syndrome)
- Iatrogenic (surgical)
- Familial
- Autoimmune
Which type of hyperfunctioning abnormality of the parathyroid is most common?
Adenoma (75-80%)
Hyperplasia is second most common
What types of bone diseases are found in hyperparathyroidism? (3)
- Osteitis fibrosis cystica - erosion of bone by osteoclasts; grossly thinned cortex; fibrosis of marrow with hemorrhage and cyst formation
- Brown tumor - osteoclasts, reactive giant cells, hemorrhage
- Osteoporosis
Which type of hyperfunctioning abnormality of the parathyroid is a solitary mass that presents with proliferation of chief cells and a rim of normal parathyroid at the periphery?
Parathyroid adenoma
How is parathyroid hyperplasia different than a parathyroid adenoma?
- In parathyroid hyperplasia, clasically all four glands are involved (vs. one with adenoma)
- Loss of normal fat cells
- No normal parathyroid along the edge
What are some distinguishing features of Parathyroid carcinomas?
- Mitotic activity
- Fibrous bands
- Caspsular vascular invasion
Why are parathyroid carcinomas difficult to treat?
- Usually not diagnosed until they become invasive or metastatic
- Hard to remove from surrounding structures due to fibrous adhesions
What are some pathologies of the adrenal cortex?
What are some pathologies of the adrenal medulla?
- Adrenal cortex:
- Adrenocortical hyperplasia
- Adenoma
- Carcinoma
- Adrenal medulla
- Pheochromocytoma
How does adrenocortical hyperplasia appear?
Which layer is predominantly hyperplastic?
Bilateral thickening of the adrenal cortex, predominantly the zona fasciculata (clear cells)
Can be diffuse or nodular (picture)
Adrenocortical adenoma
- Color:
- Predominate zone affected:
- Solitary vs multiple:
- Characteristic type of cell:
- Color: Yellow (encapsulated)
- Predominate zone affected: fasciculata
- Solitary vs multiple: solitary
- Characteristic type of cell: lipid rich cells
What distinguishes adrenocortical carcinoma from adrenocortical adenoma?
Adrenocortical carcionomas are rare and usually > 5cm in diameter
- Invasive with effacement of normal structures
- Necrosis and hemorrhage
- Well to poorly differentiated (pleomorphism)
- Lymph node metastasis
What type of adrenocortical carcinoma is shown in this image?
Well differentiated
What type of adrenocortical carcinoma is shown in this image?
Poorly differentiated
What are some causes of hypercortisolism?
- Exogenous glucocorticoids
- Increased ACTH
- ACTH independent hypercortisolism (adenoma/carcinoma)
- Congenital adrenal hyperplasia
What is Conn syndrome?
Hyperaldosteronism: Adrenal cortical adenoma
What is the classic triad of symptoms associated with pheochromocytoma?
Headaches, palpitations, diaphoresis
What is the rule of 10s that is associated with pheochromocytomas?
- 10% associated with familial syndromes
- 10% extra adenal (paragangliomas)
- 10% bilateral
- 10% are malignant
What is a distinguishing feature of pheochromocytomas?
Zellballen: small nests of chromaffin cells with abundant granular, basophilic cytoplasm
How are the chromaffin cells in a pheochromocytoma stained?
Stained with neuroendocrine markers (chromogranin, synaptophysin)
What are the common sites of paragangliomas?
- Jugulotympanic
- Carotid body
- Vagal
- Aorticopulmonary
