biology

Pituitary adenoma

Pituitary adenoma is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Pituitary adenoma rather than just read about it. In short: A pituitary adenoma is a tumor that occurs in the pituitary gland. Most pituitary tumors are benign, approximately 35% are invasive and just 0.1% to 0.2% are carcinomas.

Key takeaways

Pituitary adenoma belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Pituitary adenoma to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Pituitary adenoma from memory before moving on to harder problems.

Reference excerpt

A pituitary adenoma is a tumor that occurs in the pituitary gland. Most pituitary tumors are benign, approximately 35% are invasive and just 0.1% to 0.2% are carcinomas. Pituitary adenomas represent from 10% to 25% of all intracranial neoplasms, with an estimated prevalence rate in the general population of approximately 17%. Non-invasive and non-secreting pituitary adenomas are considered to be benign in the literal as well as the clinical sense, though a 2011 meta-analysis of available research showed that research to either support or refute this assumption was scant and of questionable quality. Adenomas exceeding 10 mm (0.39 in) in size are defined as macroadenomas, while those smaller than 10 mm (0.39 in) are referred to as microadenomas. Most pituitary adenomas are microadenomas and have an estimated prevalence of 16.7% (14.4% in autopsy studies and 22.5% in radiologic studies). The majority of pituitary microadenomas remain undiagnosed, and those that are diagnosed are often found as an incidental finding and are referred to as incidentalomas. Pituitary macroadenomas are the most common cause of hypopituitarism. While pituitary adenomas are common, affecting approximately 1 in 6 members of the general population, clinically active pituitary adenomas that require surgical treatment are rarer, affecting approximately 1 in 1,000.

Signs and symptoms

Physical Hormone secreting pituitary adenomas cause one of several forms of hyperpituitarism. The specifics depend on the type of hormone. Some tumors secrete more than one hormone, the most common combination being GH and prolactin, which present as gigantism or acromegaly and unexpected lactation (in both men and women). A patient with pituitary adenoma may present with visual field defects, classically on the left and right in bitemporal hemianopsia. It arises from the compression of the optic nerve by the tumor. The specific area of the visual pathway at which compression by these tumours occurs is at the optic chiasm. If originating superior to the optic chiasm, more commonly in a craniopharyngioma of the pituitary stalk, the visual field defect will first appear as bitemporal inferior quadrantanopia. If originating inferior to the optic chiasm the visual field defect will first appear as bitemporal superior quadrantanopia. Lateral expansion of a pituitary adenoma can also compress the abducens nerve, causing a lateral rectus palsy. Also, a pituitary adenoma can cause symptoms of increased intracranial pressure. Prolactinomas often start to give symptoms especially during pregnancy, when the increased hormone level estrogen can increase the tumor's growth rate. Various types of headaches are common in patients with pituitary adenomas. The adenoma may be the prime causative factor behind the headache or may serve to exacerbate a headache caused by other factors. Amongst the types of headaches experienced are both chronic and episodic migraine, and more uncommonly various unilateral headaches; primary stabbing headache, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) – another type of stabbing headache characterized by short stabs of pain – cluster headache, and hemicrania continua (HS). Compressive symptoms of pituitary adenomas (visual field deficits, decreased visual acuity, headaches) are more commonly seen with macroadenomas (which are greater than 10 mm in diameter) than with microadenomas (which are less than 10 mm in diameter). Non-secreting adenomas can go undetected for an extended time because no obvious abnormalities are seen; the gradual reduction in normal activities due to decreased production of hormones is rather less evident. For example, insufficient adrenocorticotropic hormone means that the adrenal glands will not produce sufficient cortisol, resulting in slow recovery from illness, inflammation, and chronic fatigue; insufficient growth hormone in children and adolescents leads to diminished stature but which can have many other explanations.

Psychiatric Various psychiatric manifestations have been associated with pituitary disorders including pituitary adenomas. Psychiatric symptoms such as depression, anxiety apathy, emotional instability, easy irritability and hostility have been noted.

Complications

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Pituitary adenoma

Start with the simplest possible case. Write down what Pituitary adenoma claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pituitary adenoma before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pituitary adenoma ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pituitary adenoma

In research: Pituitary adenoma appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Pituitary adenoma in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Pituitary adenoma is common in secondary-school and first-year university syllabi. It links to neighbouring topics Endocrine neoplasia, Neuroendocrinology, so understanding it makes those chapters shorter.
In everyday life: Look for Pituitary adenoma outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Pituitary adenoma in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pituitary adenoma means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Pituitary adenoma out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pituitary adenoma in simple terms?

A pituitary adenoma is a tumor that occurs in the pituitary gland. Most pituitary tumors are benign, approximately 35% are invasive and just 0.1% to 0.2% are carcinomas.

Why does Pituitary adenoma matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pituitary adenoma?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pituitary adenoma.