Five Flashcards
(12 cards)
Describe an andamantinomatous craniopharyngioma histologically. Where are they located? Which patients do they occur in? What are the clinical features?
1- Adamantinomatous craniopharyngioma:
Peak incidence is the first decade of life.
It represents 5% of intracranial neoplasms in the pediatric group.
The vast majority is suprasellar.
Clinical features include visual disturbance, anterior pituitary dysfunction, growth retardation, pubertal delay and diabetes insipidus.
The tumor consists of squamous epithelium with peripherally situated columnar or polygonal cells and an internal layer of loose-textured stellate reticulum. Nodules of wet keratin are present. The tumor contains cholesterol rich, machine-oil like cyst contents.
In which pts do papillary craniopharyngiomas occur? Describe its histology.
It occurs almost exclusively in adults. It often involves the third ventricle. The tumor has an arborizing appearance. The fibrovascular papillae and cyst surfaces are lined by simple squamous epithelium.
In the anterior hypophysis, which hormones are released by acidophillic cells? Basophillic? Chromophobes? How are these cells usually identified today?
Acidophilic : GH and PRL, abundant rough
endoplasmic reticulum
Basophilic: ACTH, TSH, LH, FSH
Chromophobes: few or none
secretory granules
Current classification of adenohypophysial cells is easier and better
done by IMMUNOHISTOCHEMICAL STAINS targeting secreting
hormones
What are pituitary adenomas? What are the two kinds? How do the two kinds present?
I PITUITARY ADENOM A
A. Benign tumor of anterior pituitary celts
B. May be functional (hormone-producing) or nonfunctional (silent)
1 . Nonfunctional tumors often present with mass effect.
i. Bitemporal hemianopsia occurs due to compression of the optic chiasm,
ii. Hypopituitarism occurs due to compression of normal pituitary tissue.
iii. Headache
2, Functional tumors present with features based on the type of hormone produced.
Describe the gross pathology of a pituitary adenoma. Where are they located? Describe the microscopic pathology. What is the difference between a microadenoma and macroadenoma?
•Most are well-circumscribed mass
•Larger lesions extend into suprasellar
region compressing adjacent
structures.
•Invasive Adenoma (30%): Non-
encapsulated Infiltrate adjacent bone,
dura, nasopharynx, nasal cavity
- Microscopic appearance:
Uniform population of cells - Microscopic appearance:
Lack of lobular architecture: Reticulin stain, best conventional stain to differentiate adenoma vs. normal pituitary.
According to size:
macroadenoma > 1 cm, microadenoma < 1 cm
What is a prolactinoma? How does it present in male and in females? How common is it? What is the treatment?
C. Prolactinoma presents as galactorrhea and amenorrhea (females) or as decreased libido and headache (males); most commo n type of pituitary adenoma
1 . Treatment is dopamine agonists (e.g., bromocriptine or cabergoline) to suppress prolactin production (shrinks tumor) or surgery for larger lesions.
What is a growth hormone cell adenoma? What are the two main ways it presents? What is also often present? How is it diagnosed? What is the treatment?
D. Growlh hormone cell adenoma
1 . Gigantism in children—increased linear bone growth (epiphyses are not fused)
2, Acromegaly in adults
i. Enlarged bones of hands, feet, and jaw
ii. Growth of visceral organs leading to dysfunction (e.g., cardiac failure)
iii. Enlarged tongue
1 . Secondary diabetes mellitus is often present (GH induces liver gluconeogenesis).
- Diagnosed by elevated GH and insulin growth factor-1 (1GF-1 ) levels along with lack of GH suppression by oral glucose
- Treatment is octreotide (somatostatin analog that suppresses GH release), GH receptor antagonists, or surgery.
What are ACTH cell adenomas? How common are the other pituitary adenomas?
E. ACTH cell adenomas secrete ACTH leading to Gushing syndrome (see “Adrenal Cortex” below).
F. TS H cell, LH-producing, and FSH-producing adenomas occur» but are rare.
What is hypopituitarism? When do symptoms arise? What are 3 causes? How do they present?
II. HYPOPITUITARIS M
A, Insufficient production ol hormones by the anterior pituitary gland; symptoms arise when > 75% of the pituitary parenchyma is lost,
B, Causes include
1 . Pituitary adenomas (adults) or craniopharyngioma (children)—due to mass effect or pituitary apoplexy (bleeding into an adenoma)
- Sheehan syndrome—pregnancy-related infarction of the pituitary gland
i. Gland doubles in size during pregnancy, but blood supply does not increase
significantly; blood loss during parturition precipitates infarction.
ii. Presents as poor lactation, loss of pubic liair, and fatigue - Empty sella syndrome—congenita! defect of the sella
i. Herniation of the arachnoid and CSF into the sella compresses and destroys the pituitary gland,
ii. Pituitary gland is “absent” (empLy sella) on imaging.
What is central diabetes insipidus? What causes it? What are the clinical features? How is it diagnosed? Treatment?
II. CENTRAL DIABETES INSIPIDUS
A. ADH deficiency
B. Due to hypothalamic or posterior pituitary pathology (e.g., tumor, trauma, infection,or inflammation)
C. Clinical features are based on loss of free water.
1 . Polyuria and polydipsia with risk of life-threatening dehydration
2. Hypernatremia and high serum osmolality
3. Low urine osmolality and specific gravity
D. Water deprivation test fails to increase urine osmolality (useful for diagnosis),
E. Treatment is desmopressin (ADH analog).
What is nephrogenic DI? Causes? Clinical features? Treatment?
III. NEPHROGENIC DIABETES INSIPIDUS
A. Impaired renal response to ADH
B. Due to inherited mutations or drugs (e.g., lithium and demeclocycline)
C. Clinical features are similar to central diabetes insipidus, but there is no response to
desmopressin.
What is SIADH? What causes it? What are the clinical features? Treatment?
IV. SYNDROME OF INAPPROPRIATE ADH (SIADH) SECRETION
A. Excessive ADH secretion
B. Most often due to ectopic production (e.g., small cell carcinoma of the lung); other causes include CNS trauma, pulmonary infection, and drugs (e.g., cyclophosphamide).
C. Clinical features are based on retention of free water.
1. Hyponatremia and low serum osmolality
2. Mental status changes and seizures—Hyponatremia leads to neuronal swelling and cerebral edema.
D. Treatment is free water restriction or demeclocycline.
