Pituitary/Parathyroid Pathology Flashcards
Most common hormone secreted in pituitary adenomas
Prolactin (30%) – lactotroph, acidophil
Non-secreting (null cell) is next (approx 25%)
What is Sheehan Syndrome?
Postpartum ischemic necrosis of pituitary gland
Pituitary gland enlarges in pregnancy (increased lactotrophs) –> more susceptible to ischemia, obstetrical hemorrhage or shock, results in hypopituitarism
What is the Stalk Effect?
See a slight elevation in prolactin level
Result of lack of inhibitory hypothalamic influence on prolactin
Caused by mass/destructive lesion person on stalk or hypothalamus –> NOT a prolactin-secreting adenoma
Where is a Rathke Cleft Cyst?
Sella or suptrasellar location
May produce symptoms or be asymptomatic (found at autopsy)
Columnar to cuboidal cells with cilia and occasional mucin, lining a thin walled cyst
Remnant of Rathke’s cleft pouch
Where are Craniopharyngiomas commonly located?
Usually suprasellar, may be within sella, third ventricle or rarely pineal region
When do craniopharyngiomas present?
Children (5-14 years) – adamantinomatous type
Adults (65-74 years) – usually papillary type
What are some presenting symptoms of Craniopharyngioma?
Visual abnormalities (chiasm) Hypopituitarism
What is the pathology of the Adamantinomatous type of Craniopharyngiomas?
Cysts filled with dark brown fluid (motor oil) and cholesterol crystals
Basally palisading squamous epithelium
Abundant keratin
Local invasion of brain with chronic inflammation
What is the pathology of the Papillary type of Craniopharyngiomas?
Papillary architecture
No keratin formation
What development structures give rise to the parathyroid gland?
Third pharyngeal pouch –> inferior parathyroids and thymus
Fourth pharyngeal pouch –> superior parthyroids
What kind of cells make up the parathyroid?
Chief cells – secrete PTH
Some Oxyphil cells
Large amount of intervening stream fat – in adults
Some examples of parathyroid hyperfunction
Parathyroid hyperplasia
Parathyroid adenoma
Parathyroid carcinoma
Some examples of parathyroid hypofunction
Congenital (DiGeorge syndrome)
Iatrogenic (surgical)
Familial
Autoimmune
Osteitis fibrosa cystica
bone disease in hyperparathyroidism
Erosion of bone matrix by osteoclasts
Grossly thinned cortex
Fibrosis of marrow with hemorrhage and cyst formation
Brown tumor
Bone disease in hyperparathyroidism
Osteoclasts, reactive giant cells, hemorrhage
Morphologically identical to giant cell tumor of bone
How do parathyroid adenomas look?
Solitary nodule arising in a single parathyroid gland
Composed of sheets of chief cells with decrease in stream fat
Oxyphil cells may be present
May show a rim of normal parathyroid at the periphery
How does parathyroid hyperplasia look?
Classically all four glands are involved
Morphologically there is chief cell hyperplasia
Difficult to distinguish histologically from adenoma
How do you diagnose parathyroid carcinoma?
Exceedingly rare
Usually not diagnosed until they become clearly invasive or metastatic
Mitotic activity, fibrous bands and capsular/vascular invasion
What are the three layers of the cortex and what do they secrete?
GFR = zona glomerulosa –> secretes mineralocorticoids (aldosterone)
zona fasiculalta –> secretes glucocoritcoids (cortisol)
zona reticulata –> secretes sex steroids (estrogens and androgens)
What is the medulla composed of?
Chromatin cells – catecholamines (epinephrine)
What is adrenocortical hyperplasia?
Bilateral thickening of the adrenal cortex (diffuse and nodular)
Predominantly fasiculata cells
Resembles adrenocortical adenoma microscopically
What is an adrenocortical adenoma?
Yellow, encapsulated solitary lesion
Predominantly zona fasiculata cells – like hyperplasia
Can be function or non-functional
What is adrenocortical carcinoma?
Rare
Invasive, with effacement of normal structures
Necrosis and hemorrhage will be present
Well to poorly differentiated
Tendency to invade the adrenal vein and vena cava
Lymph node metastasis
What are some features that are more likely seen in adrenocortical carcinoma?
Well-differentiated tumors may be very difficult to distinguish from adenomas Large size >5cm Capsular and vascular invasion Necrosis Increased mitosis Cellular pleomorphism
What will the adrenals look like in hypercortisolism d/t exogenous glucocorticoids?
Cortical atrophy
What will the adrenals look like in hypercortisolism d/t increased ACTH (pituitary adenoma)?
Bilateral hyperplasia
What will the adrenals look like in hypercortisolism d/t ACTH independent hypercortisol?
There is probably some sort of adrenocortical adenoma or carcinoma secreting cortisol w/o ACTH stimulation
What is a common cause of hyperaldosteronism?
Adrenal cortical adenoma (Conn syndrome)
What do the adrenals look like with congenital adrenal hyperplasia (CAH)?
Bilateral hyperplasia
Where is a pheochromocytoma located?
Neoplasm in the adrenal medulla composed of chromatin cells
Classic triad of pheochromocytoma
Headaches
Palpitations
Diaphoresis
How do you know if a pheochromocytoma is malignant?
Metastasis
Microscopic appearance of pheochromocytoma
“Zellballen” - cell balls = nests of cells within a rich vascular network
Abundant cytoplasm that is granular, often basophilic
Widely variable cytology – mature chromatin cells to highly pleomorphic cells
What types of cells are chromaffin cells?
Neuroendocrine cells
What is a paraganglioma?
Extra adrenal pheochromocytoma
Almost all are non-functional
Similar morphology to pheochromocytoma
Common sites = jugulotympanic, carotid body, vagal, aorticopulmonary
