Hypothalamic and Pituitary Pathology Flashcards
1
Q
Normal anterior pituitary histology
A
- Acinar pattern maintained
- H&E stain: AP shows different cell types
- PAS-orange G stain: AP demonstrates greater distinction of cell types (acidophils, basophils, chromophobes)
- Lateral wings: mostly populated by acidophilic GH secreting cells (maintenance of acinar structure)
2
Q
Normal posterior pituitary histology
A
- Manifests eosinophilic fibrillar appearance
- Occasionally swollen axonal processes (Herring bodies) found
- Abundant axons by antineurofilament staining
- Infundibular stalk:
- Congested, thin-walled, closely juxtaposted hypothalamic hypophyseal portal system
3
Q
Pituitary adenoma pathology
A
- Makes hormones without regulation (unchecked in production)
- Most are sporadic - less than 5% familial
- Carcinomas exist but are exceedingly rare
- MEN1, CDKN1B, PRKAR1A, AIP
- Not caused by end organ signals, not sure what causes them
- Two sizes
- Microadenomas
- < 10 mm
- Confined to sellar region
- Can cause some hypofunction or rarely DI
- Macroadenomas
- > 10 mm
- Distort adjacent tissue, erode sella –> symptoms of mass effect (bitemporal hemianopsia)
- Microadenomas
4
Q
Symptoms of pituitary adenoma
A
- Symptoms from hypersecretion
- Acromegaly
- Cushing’s disease
- Amenorrhea/galactorrhea
- Symptoms from mass effect
- Headaches
- Vision field defect –> lateral visual field/mesial retinal –> bitemporal hemianopsia
- Cranial nerve palsies –> ptosis + diplopia
- Pituitary hormone deficits –> panhypopituitarism
- Rarely: seizures (lateral growth), stroke, CSF leak
5
Q
Treatment goals of pituitary adenoma
A
- Control mass effects
- Preserve pituitary function
- Prevent recurrence
- Relieve symptoms
- Improve mortality rates
- Control hormone hypersecretion
- Use medical therapy, surgery, radiation, careful observation
6
Q
Pituitary adenoma histology
A
- Abundant exfoliation of cytologically monotonous cells
- Nuclear pleiomorphism has no prognostic significance (rarely found)
- Mitoses rare, but occasionally seen in macroadenomas (slow-growing)
- Near-signature perivascular arrangement of tumor cells (somewhat simulating ependymoma)
- Clear-cell appearance somewhat simulates oligodendroglioma
- Reticulin: single most informative histochemical stain for adenomas
- Contrasts disrupted reticulin pattern of adenoma with preserved, nested pattern in normal compressed gland
7
Q
Gonadotroph cell adenoma histology
A
- Sheet-like architectural pattern - most common in surgery
- No acini, sheet-like –> not good prognosis\
- Higher power magnification: Contains cells with abundant, oncocytic cytoplasm in one area and cells with scant cytoplasm in other regions
- Immunoreactivity for alpha-subunit
- Don’t know how much is getting out of cell
- Most patients are not hypersecretory
- Immunoreactivity for FSH
- Patchy distribution characteristic
- Generally no physiologic effect
8
Q
Types and prevalence of of AP tumors
A
- Most common at autopsy:
- Prolactinomas
- Null cell
- Gonadotroph
- Excess hormone production is not OK
- Different distribution of most common at autopsy vs. those that need surgery
9
Q
Other types of hypothalamic/pituitary lesions that can lead to pituitary dysfunction (7)
A
- Pituitary apoplexy
- Rathke cleft cysts
- Lymphocytic hypophysitis
- Craniopharyngioma
- Germinoma
- Meningioma
- Hamartoma
10
Q
Pituitary apoplexy
A
- Old term (apoplexy = collapse)
- Sudden hemorrhage or infarction of pituitary gland
- Occurs in 10-15% of pituitary adenomas
- Occurs in macroadenomas but not always size dependent
- Can cause AP dysfunction
- Often occurs in non-clinically evident tumors
- Symptoms
- Sudden headache
- Acute vision changes
- Ophthalmoplegia
- Altered mental status
11
Q
Rathke cleft cysts
A
- Present two ways
- Terrible headache with MRI –> have to determine if related
- Incidental findings
- Rarely malignant
12
Q
Lymphocytic hypophysitis
A
- Autoimmune disorder classically seen in post-partum women
- Inflammatory condition –> bright on post-contrast studies
- Completely mimics pituitary adenoma, including on neuroimaging
- Dx cannot be confidently made until histological confirmation
- Sheets of cytologically bland pure lymphocytic infiltrates (not neoplastic)
- Infiltrates hypothalamus + infundibulum which adenoma does not
- Not a singular disease but rather a collection of different entities
13
Q
Craniopharyngioma
A
- Suprasellar calcified mass in pediatric patients
- Lots in pediatric realm
- Tends to calcify more than pituitary adenoma
14
Q
Germinoma
A
- Germ cell tumors occurs in gonads or midline sites of body
- Suprasellar or pineal gland most common
- WHO grade 4
- Can be mistaken for adenoma
- Radiation + chemotherapy
- Pediatric: causes cognitive problems
15
Q
Meningioma
A
- Occur because meninges are nearby
- Differentiate by where tumor arises from
- Determine if gland has distorted shape or normal flat bottom
- Broad dural base: tumor comes from around the pituitary
- Broad dural tail
- Determine if gland has distorted shape or normal flat bottom
- Classic location plan, sphenoid alley
- All kinds of subclassifications/classifications
