Flashcards: Pituitary Adenomas — 55 cards

What is a pituitary adenoma?

A benign tumor arising from the pituitary gland.

How are pituitary adenomas classified?

By size and hormonal function.

Since when are pituitary adenomas called PitNETs?

Since 2017.

Why are pituitary adenomas called pituitary neuroendocrine tumors?

Because some can be aggressive and cause oncological problems.

What is the prevalence of pituitary adenomas?

78 to 94 per 100,000 inhabitants.

What is the incidence of pituitary adenomas per year?

4 per 100,000 inhabitants per year.

What mutation causes the gsp oncogene in somatotroph adenomas?

An activating mutation of the alpha subunit of G proteins.

What percentage of somatotroph adenomas have the gsp oncogene?

40%.

Which gene's germline mutations cause some familial pituitary adenomas?

The AIP gene.

Are AIP gene mutations involved in sporadic pituitary tumorigenesis?

No, they do not appear to be involved.

What distinguishes functional from nonfunctional pituitary adenomas?

Functional adenomas secrete hormones; nonfunctional do not cause hormone hypersecretion.

What size defines a microadenoma in millimeters?

Less than 10 mm.

What size defines a macroadenoma in millimeters?

More than 10 mm.

What is the extent of Hardy stage A adenomas?

Strictly intrasellar.

Where does Hardy stage B adenoma extend?

Suprasellarly toward the optic chiasm.

What does Knosp grade 1 indicate about cavernous invasion?

No cavernous invasion.

What does Knosp grade 4 indicate about the internal carotid artery?

Complete encasement of the internal carotid artery.

Which families does the WHO 2017 classify adenomas into?

PIT1, Tpit, and SF1 families.

What pituitary hormones does immunohistochemistry detect?

Prolactin, TSH, GH, ACTH, FSH, LH, and the alpha subunit.

What defines Trouillas grade 1a pituitary tumors?

Noninvasive and nonproliferative.

What defines Trouillas grade 1b pituitary tumors?

Noninvasive but proliferative.

What defines Trouillas grade 2a pituitary tumors?

Invasive but nonproliferative.

What defines Trouillas grade 2b pituitary tumors?

Invasive and proliferative.

What defines Trouillas grade 3 pituitary tumors?

Metastatic pituitary carcinoma.

What symptoms are included in the tumor syndrome related to the orbit?

Retro-orbital headaches and visual disturbances.

Which visual impairments occur in large tumor lesions?

Reduced visual acuity and visual-field defects.

What syndrome may involve ocular motor nerves in tumor syndrome?

Cavernous sinus syndrome.

What are the abrupt symptoms of pituitary apoplexy?

Severe headache, meningeal syndrome, ocular motor paralysis, confusion or coma, and acute visual disturbance.

What causes acute visual disturbance in pituitary apoplexy?

Chiasmal compression.

What conditions can cause hyperprolactinemia besides prolactinoma?

Pituitary stalk disconnection, medications, renal failure, liver failure, polycystic ovary syndrome, and hypothyroidism.

Which symptom occurs in 90% of women with hyperprolactinemia?

Amenorrhea.

What is the first-line treatment for prolactinomas?

Dopamine agonists including bromocriptine, quinagolide, and cabergoline.

What are common symptoms of acromegaly related to extremities and skin?

Enlarged extremities and thick oily skin.

What growth hormone nadir level after oral glucose tolerance test supports acromegaly diagnosis?

Greater than 0.1 micrograms per liter (1 IU per liter).

What is the primary treatment for somatotroph adenoma?

Surgical treatment.

When is radiotherapy used in treating somatotroph adenoma?

After surgical failure.

When is medical therapy indicated for somatotroph adenoma?

When surgery or radiotherapy is contraindicated or before surgery for invasive tumors.

What symptoms can corticotroph adenoma cause related to muscles and skin?

Proximal and abdominal muscle wasting and thin bruisable skin.

Which metabolic abnormalities are caused by corticotroph adenoma?

Hypertension, glucose intolerance, hypokalemia, and hypercalciuria.

How is cortisol affected in corticotroph adenoma?

Cortisol is elevated with loss of its circadian rhythm.

What is the ACTH response in corticotroph adenoma to low- and high-dose suppression tests?

ACTH is elevated but suppressible with the high-dose test; low-dose suppression tests are negative.

What is the reference imaging for detecting pituitary adenomas?

MRI is the reference examination for detecting pituitary microadenomas and macroadenomas.

What percentage of brain tumors are pituitary adenomas?

10%.

What proportion of pituitary adenomas are gonadotroph adenomas?

15% to 40%.

Name one molecular abnormality involved in pituitary tumorigenesis besides mutations.

PTTG overexpression.

What epigenetic abnormality is involved in pituitary tumorigenesis?

Promoter-region hypermethylation.

What characterizes Hardy sellar grade 1?

An intact sellar floor.

What characterizes Hardy sellar grade 3?

Destroyed sellar floor with invasive extension into the sphenoid sinus.

When is an atypical adenoma suggested by Ki-67, mitoses, and p53?

Ki-67 above 3%, more than 2 mitoses/10 HPF, and p53 positivity in over 10 nuclei/10 HPF.

What does emergency imaging show in suspected pituitary apoplexy?

An adenoma undergoing necrosis or hemorrhage.

When is surgery considered for macroadenomas?

When medical treatment is intolerable or ineffective, visual-field improvement is absent, or neurological pituitary apoplexy occurs.

Which complications can acromegaly cause in the cardiovascular and metabolic systems?

Myocardial hypertrophy and glucose intolerance.

What percentage of pituitary adenomas are thyrotroph adenomas?

Less than 1%.

What thyroid hormone abnormalities occur in thyrotroph adenoma?

Elevated free T4 with nonsuppressed normal or elevated TSH.

What reproductive symptoms can gonadotroph adenoma cause in men and women?

Amenorrhea or ovarian hyperstimulation in women; hypogonadism or testicular stimulation in men.