Pituitary/Parathyroid Pathology

Question 1

Most common hormone secreted in pituitary adenomas

Answer 1

Prolactin (30%) – lactotroph, acidophil

Non-secreting (null cell) is next (approx 25%)

Question 2

What is Sheehan Syndrome?

Answer 2

Postpartum ischemic necrosis of pituitary gland
Pituitary gland enlarges in pregnancy (increased lactotrophs) –> more susceptible to ischemia, obstetrical hemorrhage or shock, results in hypopituitarism

Question 3

What is the Stalk Effect?

Answer 3

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

Question 4

Where is a Rathke Cleft Cyst?

Answer 4

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

Question 5

Where are Craniopharyngiomas commonly located?

Answer 5

Usually suprasellar, may be within sella, third ventricle or rarely pineal region

Question 6

When do craniopharyngiomas present?

Answer 6

Children (5-14 years) – adamantinomatous type

Adults (65-74 years) – usually papillary type

Question 7

What are some presenting symptoms of Craniopharyngioma?

Answer 7

Visual abnormalities (chiasm)
Hypopituitarism

Question 8

What is the pathology of the Adamantinomatous type of Craniopharyngiomas?

Answer 8

Cysts filled with dark brown fluid (motor oil) and cholesterol crystals
Basally palisading squamous epithelium
Abundant keratin
Local invasion of brain with chronic inflammation

Question 9

What is the pathology of the Papillary type of Craniopharyngiomas?

Answer 9

Papillary architecture

No keratin formation

Question 10

What development structures give rise to the parathyroid gland?

Answer 10

Third pharyngeal pouch –> inferior parathyroids and thymus

Fourth pharyngeal pouch –> superior parthyroids

Question 11

What kind of cells make up the parathyroid?

Answer 11

Chief cells – secrete PTH
Some Oxyphil cells
Large amount of intervening stream fat – in adults

Question 12

Some examples of parathyroid hyperfunction

Answer 12

Parathyroid hyperplasia
Parathyroid adenoma
Parathyroid carcinoma

Question 13

Some examples of parathyroid hypofunction

Answer 13

Congenital (DiGeorge syndrome)
Iatrogenic (surgical)
Familial
Autoimmune

Question 14

Osteitis fibrosa cystica

Answer 14

bone disease in hyperparathyroidism
Erosion of bone matrix by osteoclasts
Grossly thinned cortex
Fibrosis of marrow with hemorrhage and cyst formation

Question 15

Brown tumor

Answer 15

Bone disease in hyperparathyroidism
Osteoclasts, reactive giant cells, hemorrhage
Morphologically identical to giant cell tumor of bone

Question 16

How do parathyroid adenomas look?

Answer 16

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

Question 17

How does parathyroid hyperplasia look?

Answer 17

Classically all four glands are involved
Morphologically there is chief cell hyperplasia
Difficult to distinguish histologically from adenoma

Question 18

How do you diagnose parathyroid carcinoma?

Answer 18

Exceedingly rare
Usually not diagnosed until they become clearly invasive or metastatic
Mitotic activity, fibrous bands and capsular/vascular invasion

Question 19

What are the three layers of the cortex and what do they secrete?

Answer 19

GFR = zona glomerulosa –> secretes mineralocorticoids (aldosterone)
zona fasiculalta –> secretes glucocoritcoids (cortisol)
zona reticulata –> secretes sex steroids (estrogens and androgens)

Question 20

What is the medulla composed of?

Answer 20

Chromatin cells – catecholamines (epinephrine)

Question 21

What is adrenocortical hyperplasia?

Answer 21

Bilateral thickening of the adrenal cortex (diffuse and nodular)
Predominantly fasiculata cells
Resembles adrenocortical adenoma microscopically

Question 22

What is an adrenocortical adenoma?

Answer 22

Yellow, encapsulated solitary lesion
Predominantly zona fasiculata cells – like hyperplasia
Can be function or non-functional

Question 23

What is adrenocortical carcinoma?

Answer 23

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

Question 24

What are some features that are more likely seen in adrenocortical carcinoma?

Answer 24

Well-differentiated tumors may be very difficult to distinguish from adenomas
Large size >5cm
Capsular and vascular invasion
Necrosis
Increased mitosis 
Cellular pleomorphism

Question 25

What will the adrenals look like in hypercortisolism d/t exogenous glucocorticoids?

Answer 25

Cortical atrophy

Question 26

What will the adrenals look like in hypercortisolism d/t increased ACTH (pituitary adenoma)?

Answer 26

Bilateral hyperplasia

Question 27

What will the adrenals look like in hypercortisolism d/t ACTH independent hypercortisol?

Answer 27

There is probably some sort of adrenocortical adenoma or carcinoma secreting cortisol w/o ACTH stimulation

Question 28

What is a common cause of hyperaldosteronism?

Answer 28

Adrenal cortical adenoma (Conn syndrome)

Question 29

What do the adrenals look like with congenital adrenal hyperplasia (CAH)?

Answer 29

Bilateral hyperplasia

Question 30

Where is a pheochromocytoma located?

Answer 30

Neoplasm in the adrenal medulla composed of chromatin cells

Question 31

Classic triad of pheochromocytoma

Answer 31

Headaches
Palpitations
Diaphoresis

Question 32

How do you know if a pheochromocytoma is malignant?

Answer 32

Metastasis

Question 33

Microscopic appearance of pheochromocytoma

Answer 33

“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

Question 34

What types of cells are chromaffin cells?

Answer 34

Neuroendocrine cells

Question 35

What is a paraganglioma?

Answer 35

Extra adrenal pheochromocytoma
Almost all are non-functional
Similar morphology to pheochromocytoma
Common sites = jugulotympanic, carotid body, vagal, aorticopulmonary