Pituitary Tumors and Adenomas

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Questions and Answers

What percentage of clinically recognized cases are accounted for by lactotroph adenomas?

20%

30% (correct)

10%

40%

What is the characteristic of sparsely granulated lactotroph adenomas?

Diffuse cytoplasmic PIT-1 localization

Juxtanuclear localization of the transcription factor PIT-1 (correct)

Absence of PIT-1 localization

PIT-1 localization only in the nucleus

What is the term for the condition caused by excessive growth hormone secretion in children?

Acromegaly

Nelson syndrome

Cushing syndrome

Gigantism (correct)

What is the characteristic of eosinophilic densely granulated lactotroph adenomas?

Diffuse cytoplasmic PIT-1 localization Signup and view all the answers

What is the term for the syndrome caused by excessive secretion of adrenocorticotropic hormone (ACTH)?

Cushing syndrome Signup and view all the answers

What is the local mass effect of pituitary tumors?

Radiographic abnormalities of the sella turcica Signup and view all the answers

What percentage of pituitary adenomas are thyrotroph adenomas?

1% Signup and view all the answers

What is a common symptom of gonadotroph adenomas in premenopausal women?

Amenorrhea Signup and view all the answers

What is a characteristic of plurihormonal adenomas?

They are usually aggressive Signup and view all the answers

What is a common presentation of null cell adenomas?

Symptoms stemming from mass effects Signup and view all the answers

What can cause hypopituitarism in null cell adenomas?

Both A and B Signup and view all the answers

What is a common feature of gonadotroph adenomas?

They are nonfunctioning Signup and view all the answers

What is the result of dystrophic calcification in lactotroph adenomas?

Extensive calcification, also known as a 'pituitary stone' Signup and view all the answers

What is the correlation between serum prolactin concentrations and the size of the adenoma?

Serum prolactin concentrations are directly proportional to the size of the adenoma Signup and view all the answers

What are the symptoms of hyperprolactinemia in women?

Amenorrhea, galactorrhea, and loss of libido Signup and view all the answers

What is the diagnosis of lactotroph adenoma more readily made in?

Women between 20 and 40 years of age Signup and view all the answers

What is the result of a suprasellar mass on prolactin secretion?

Disturbance of the inhibitory influence of the hypothalamus on prolactin secretion Signup and view all the answers

What is the result of a growth hormone (GH)-secreting somatotroph adenoma in children?

Gigantism Signup and view all the answers

What is a likely contributor to shortness of breath and decreased exercise capacity?

Reduced cardiac output Signup and view all the answers

What is a characteristic feature of the skin in this condition?

Nonpitting edema Signup and view all the answers

What is the most useful single screening test for hyperthyroidism?

Measurement of serum TSH concentration Signup and view all the answers

What is a common symptom of hypothyroidism?

Unexplained increase in body weight Signup and view all the answers

What happens to TSH levels in primary hypothyroidism?

They increase Signup and view all the answers

What is not a feature of hypothyroidism due to primary hypothalamic or pituitary disease?

Normal TSH levels Signup and view all the answers

What is the typical age distribution of craniopharyngiomas?

A bimodal age distribution with one peak in childhood and a second peak in adults Signup and view all the answers

What is a common presenting symptom of craniopharyngiomas in children?

Growth retardation due to pituitary hypofunction Signup and view all the answers

What is the characteristic morphology of craniopharyngiomas?

Average 3 to 4 cm in diameter, sometimes cystic and multiloculated Signup and view all the answers

Which type of craniopharyngioma is more commonly observed in adults?

Papillary craniopharyngioma Signup and view all the answers

What is a diagnostic feature of adamantinomatous craniopharyngioma?

Compact, lamellar keratin formation Signup and view all the answers

What is a frequent finding in adamantinomatous craniopharyngioma?

Dystrophic calcification Signup and view all the answers

Study Notes

Pituitary Adenomas

Gonadotroph adenomas are difficult to recognize due to small hormone secretion and non-recognizable clinical syndrome.
They frequently present in middle-aged men and women with neurologic symptoms, such as impaired vision, headaches, diplopia, or pituitary apoplexy.
Pituitary hormone deficiencies, including impaired LH secretion, may occur, causing decreased energy and libido in men and amenorrhea in premenopausal women.

Thyrotroph Adenomas

Thyrotroph adenomas are rare, accounting for approximately 1% of pituitary adenomas.
They are a rare cause of hyperthyroidism.
These tumors express PIT-1, similar to lactotroph and somatotroph adenomas.

Plurihormonal Adenomas

Plurihormonal adenomas secrete multiple hormones and are usually aggressive.
Most are derived from cells of PIT-1–expressing lineage.

Null Cell Adenomas

Null cell adenomas do not express any markers of hormonal or lineage differentiation.
They typically present with symptoms stemming from mass effects.
These lesions may also compromise the residual anterior pituitary, causing hypopituitarism, which may appear gradually or abruptly due to pituitary apoplexy.

Pituitary Carcinomas and Blastomas

Local mass effects may be produced by any type of pituitary tumor.
These effects include radiographic abnormalities of the sella turcica, visual field abnormalities, signs and symptoms of elevated intracranial pressure, and occasionally hypopituitarism.

Comparison of Pituitary Adenomas

Lactotroph adenomas are the most common type of hyperfunctioning pituitary adenoma, accounting for about 30% of clinically recognized cases.
Somatotroph adenomas cause gigantism in children and acromegaly in adults.
Corticotroph adenomas, gonadotroph adenomas, thyrotoph adenomas, and "plurihormonal" adenomas and "null cell" adenomas have distinct epidemiology, morphology, and clinical features.

Definition of Terms

Gigantism: excess growth hormone secretion in children.
Acromegaly: excess growth hormone secretion in adults.
Cushing syndrome: excess glucocorticoid secretion.
Nelson syndrome: rapid growth of a pituitary tumor after bilateral adrenalectomy for Cushing's disease.
Crooke cell adenoma: a type of pituitary adenoma.

Craniopharyngiomas

Craniopharyngiomas are a type of pituitary tumor that can cause growth retardation due to pituitary hypofunction and GH deficiency.
They can encroach on the optic chiasm or cranial nerves and may bulge into the floor of the third ventricle and base of the brain.
Two distinct histologic variants are recognized: adamantinomatous craniopharyngioma and papillary craniopharyngioma.

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Description

This quiz covers the local mass effects of pituitary tumors, including radiographic abnormalities, visual field defects, and signs of elevated intracranial pressure. It also touches on the unpredictable biologic behavior of pituitary adenomas.