Familial isolated pituitary adenoma

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Familial isolated pituitary adenoma (FIPA) is an inherited condition characterized by development of a noncancerous tumor in the pituitary gland (called a pituitary adenoma). The pituitary gland, which is found at the base of the brain, produces hormones that control many important body functions.

Tumors that form in the pituitary gland can release excess levels of one or more hormones, although some tumors do not produce hormones (nonfunctioning pituitary adenomas). Those that do are typically distinguished by the particular hormones they produce. Prolactinomas are the most common tumors in FIPA. These tumors release prolactin, a hormone that stimulates breast milk production in females. Both women and men can develop prolactinomas, although they are more common in women. In women, these tumors may lead to changes in the menstrual cycle or difficulty becoming pregnant. Some affected women may produce breast milk, even though they are not pregnant or nursing. In men, prolactinomas may cause erectile dysfunction or decreased interest in sex. Rarely, affected men produce breast milk. Large prolactinomas can press on nearby tissues such as the nerves that carry information from the eyes to the brain (the optic nerves), causing problems with vision.

Another type of tumor called somatotropinoma is also common in FIPA. These tumors release growth hormone (also called somatotropin), which promotes growth of the body. Somatotropinomas in children or adolescents can lead to increased height (gigantism), because the long bones of their arms and legs are still growing. In adults, growth of the long bones has stopped, but the tumors can cause overgrowth of the hands, feet, and face (acromegaly) as well as other tissues.

Less common tumor types in FIPA include somatolactotropinomas, nonfunctioning pituitary adenomas, adrenocorticotropic hormone-secreting tumors (which cause a condition known as Cushing disease), thyrotropinomas, and gonadotropinomas. In a family with the condition, affected members can develop the same type of tumor (homogenous FIPA) or different types (heterogenous FIPA).

In FIPA, pituitary tumors usually occur at a younger age than sporadic pituitary adenomas, which are not inherited. In general, FIPA tumors are also larger than sporadic pituitary tumors. Often, people with FIPA have macroadenomas, which are tumors larger than 10 millimeters.

Familial pituitary adenomas can occur as one of many features in other inherited conditions such as multiple endocrine neoplasia type 1 and Carney complex; however, in FIPA, the pituitary adenomas are described as isolated because only the pituitary gland is affected.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

FIPA can be caused by mutations in the AIP gene. The function of the protein produced from this gene is not well understood, but it is thought to act as a tumor suppressor, which means it helps prevent cells from growing and dividing in an uncontrolled way. Mutations in the AIP gene alter the protein or reduce the production of functional protein. These changes likely impair the ability of the AIP protein to control the growth and division of cells, allowing pituitary cells to grow and divide unchecked and form a tumor. It is not known why the pituitary gland is specifically affected or why certain types of pituitary adenomas develop.

AIP gene mutations account for approximately 15 to 25 percent of cases of FIPA. Somatotropinomas are the most common type of tumor in these individuals. The tumors usually occur at a younger age, often in childhood, and are larger than FIPA tumors not caused by AIP gene mutations. The other genetic causes of FIPA are unknown.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

FIPA is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. However, only 20 to 30 percent of individuals with an AIP gene mutation develop a pituitary adenoma. This phenomenon, in which some individuals with a mutation do not develop the features of a particular disorder, is called incomplete penetrance.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Pituitary adenomas, including sporadic tumors, are relatively common; they are identified in an estimated 1 in 1,000 people. FIPA, though, is quite rare, accounting for approximately 2 percent of pituitary adenomas. More than 200 families with FIPA have been described in the medical literature.

Which doctor should you see?

The suggested department for discussing Familial isolated pituitary adenoma is Endocrinology, with a endocrinologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which hormone or metabolic finding is important in this case?
• How should test timing and current medicines be taken into account?
• What follow-up would show whether the care plan is working?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Familial isolated pituitary adenoma. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.