Endocrine Pathology I Flashcards
(30 cards)
What are the main causes of Hyperpituitarism?
- Pituitary adenoma (most common)
- Hyperplasia
- Carcinomas (<1%)
- Ectopic hormone production from non-pituitary tumors
- Hypothalamic disorders
What are the general features of all pituitary adenomas?
- Arise from anterior pituitary
- Functional or nonfunctional
- Peak: 35–60 years
- Microadenomas <1 cm; Macroadenomas >1 cm
- Diagnosed by immunohistochemical stains
What genetic mutations are associated with pituitary adenomas?
- Sporadic (95%): G-protein α-subunit mutation → ↑ GTPase activity
- Familial: MEN1, CDKN1B, PRKAR1A, AIP
- Aggressive tumors: Cyclin D1 overexpression, p53 mutation, RB1 silencing
What are key morphological features of pituitary adenomas?
- Soft, well-circumscribed; can be invasive
- Sheets of uniform cells with absent reticulin network
- Atypical adenomas: ↑ mitotic activity, positive p53 → more aggressive
What are the clinical effects of pituitary adenomas?
- Hormonal excess: depends on tumor type
- Mass effects: visual field defects, ↑ intracranial pressure, sella turcica changes, pituitary apoplexy
What is a Prolactinoma and what is the treatment?
Most common pituitary adenoma causing an ↑ Prolactin → amenorrhea, galactorrhea, ↓ libido, infertility
- can also result from drugs, estrogens, renal failure
Treatment: Bromocriptine or surgery
What is a Somatotropinoma and what is the treatment?
2nd most common adenoma causing an ↑ GH → ↑ IGF-1 which leads to giantism in children and acromegaly in adults
- Treatment: Surgery or somatostatin analogs
What is a ACTH Cell Adenoma and what does it lead to?
usually a small microadenoma at diagnosis that causes ↑ ACTH → Cushing disease (hypercortisolism)
- causes weight gain, moon face, and central obesity
What is a bihormonal adenoma?
Tumor that secretes both prolactin and GH
- Shows combined clinical effects of both hormones
What are the features of non-functioning pituitary adenomas?
- 25–30% of pituitary tumors
- No hormone symptoms
- Present with mass effects (vision loss, pressure symptoms)
What is MEN 1 Syndrome (Multiple Endocrine Neoplasia Type 1)?
Formerly: Wermer Syndrome –> autosomal dominant mutation in MEN1 gene on chromosome 11q13 causing tumors of:
- Parathyroid
- Anterior pituitary
- Pancreas
or non-endocrine tumors
- facial angiofibromas
- Meningiomas
- Ependymomas
What are the causes of Hypopituitarism?
- Ischemic injury, surgery, radiation
- Inflammatory reactions
- Nonfunctional adenomas
What must occur for Clinical hypopituitarism to be present?
≥75% of the anterior pituitary (parenchyma) must be destroyed
- damage is usually due to a destructive process
What are the clinical manifestations of Hypopituitarism?
- GH deficiency → Dwarfism
- LH/FSH deficiency → Amenorrhea, infertility
- TSH deficiency → Hypothyroidism
- ACTH deficiency → Hypoadrenalism
- Prolactin deficiency → Failure of lactation
What is Pituitary Apoplexy?
Sudden bleeding or infarction in the pituitary gland due often to unrecognized pituitary tumor (80% undiagnosed before apoplexy)
What are the main symptoms and presentations of Pituitary Apoplexy?
- Acute headache, visual disturbances, altered mental status
- Visual symptoms due to: Compression of optic chiasm → visual field defects, Compression of cranial nerves in cavernous sinus → ocular dysfunction
- Endocrine crisis: hormone deficiencies
What are the Posterior Pituitary Syndromes?
- Diabetes Insipidus (DI): ADH deficiency → central DI (↓ production) or Nephrogenic DI (renal unresponsiveness) → causes polyuria, hypernatremia, polydipsia
- Syndrome of Inappropriate ADH Secretion (SIADH): Excessive ADH → Water retention, hyponatremia, cerebral edema → causes CNS disorders, ectopic ADH
What are the consequences of lesions to the Hypothalamus?
Disrupt hypothalamic–pituitary axis →
- Hypopituitarism
- Hyperprolactinemia
- May also cause visual field defects
What are Hypothalamic Suprasellar Tumors and what are the types?
tumors that can cause hypo/hyperfunction of anterior pituitary that may result in diabetes insipidus
- Types → Gliomas, Craniopharyngiomas
What is a Craniopharyngiomas and what are the genetic risk factors?
Benign, slow-growing tumor (1–5% of intracranial tumors) with a bimodal age distribution (5–15 & 45–65 years)
- mainly derived from Rathke’s pouch remnants
- often cystic and multiloculated
- WNT pathway abnormalities
- Mutation in β-catenin gene
What are the two histological types of Craniopharyngiomas?
- Adamantinomatous (children): Squamous epithelium, wet keratin, calcification, “machine oil” cyst fluid
- Papillary (adults): Lack keratin, no calcification/cysts
What is the prognosis of Craniopharyngiomas?
Typically non-recurrent and excellent survival
What are Gliomas and what is the most common subtype?
tumors of glial origin, astrocytomas are the most common subtype.
- Fibrillary astrocytomas represent ~80% of adult primary brain tumors and typically arise in the cerebrum –> characterized by astrocytic nuclei dispersed in a background of glial tissue with varying cellular density.
What are the Histological Features of Low-Grade Gliomas?
- Poorly defined (gray/white infiltrative masses)
- Exhibit: Hypercellularity, Nuclear pleomorphism
- Behavior: May be indolent (slow-growing or static), can remain stable for years with minimal symptoms, eventually may progress rapidly → worsening clinical condition and prognosis
***Mean survival: >5 years (for low-grade gliomas)
