A pituitary adenoma is a benign tumor in the front part of the pituitary gland. Doctors categorize these tumors by size, with the smallest type called pituitary microadenoma.
Pituitary adenomas are tumors that begin in the larger front — anterior — part of the pituitary gland. They are often noncancerous — benign — and slow growing.
Functioning or secretory pituitary adenomas secrete hormones from the anterior pituitary. Nonfunctioning or non-secretory adenomas
This article discusses pituitary microadenoma, its symptoms, causes, diagnosis, and more.
Because the pituitary gland is part of the endocrine system, it is called endocrine neoplasia, or tumor. Most pituitary adenomas are
Pituitary microadenomas are the
People with microadenoma often do not show symptoms.
Tumors often do not grow larger than 1 cm and do not press on or damage brain structures, blood vessels, or nerves.
When they compress tissue in the anterior pituitary gland, they may reduce the production of different pituitary hormones, leading to hypopituitarism.
However, functioning pituitary microadenomas may cause hormonal imbalances, which can produce a number of symptoms.
Adenomas that secrete prolactin can cause:
- a decreased libido
- a lack of menses — amenorrhea — and milky, nipple discharge — galactorrhea — in females
- erectile dysfunction and breast enlargement — gynecomastia — in males
Growth hormone (GH) secreting adenoma can lead to:
- vision changes
- changes in shoe or ring size
- carpal tunnel syndrome
- excessive sweating
- conditions, such as hypertension, cardiomyopathy, colon polyps, and obstructive sleep apnea
Tumors secreting adrenocorticotropic hormone (ACTH) can cause Cushing’s syndrome, which presents with:
- weight gain
- muscle weakness
- a mood disorder
- multiple fractures
- easy bruising
Adenomas secreting thyroid-stimulating hormone (TSH) can cause individuals to experience:
- weight loss
- goiter, which is the growth of the thyroid gland
Experts do not know the cause of pituitary adenomas. Most tend to
About 5% of all pituitary tumors run in families.
Pituitary adenomas may occur in syndromes. Individuals with the
- multiple endocrine neoplasia type 1 (MEN1)
- Carney complex (CNC)
- familial isolated pituitary adenomas (FIPA)
- isolated familial acromegaly
Doctors mainly detect pituitary microadenomas on routine CT imaging tests for other reasons.
Doctors may request an MRI, which is much more sensitive than a CT scan. An MRI with gadolinium can distinguish the mass from an aneurysm.
The Endocrine Society clinical practice guidelines also
Individuals with nonfunctioning microadenomas do not require surgery but need an annual checkup, so doctors can monitor the tumor’s growth and the development of hypopituitarism.
For prolactin-secreting adenomas, the treatment of choice is dopamine agonists, such as cabergoline. This helps normalize prolactin levels and decrease the tumor size. Doctors may recommend surgery for tumors that are resistant to medical treatment.
Trans-sphenoidal surgery is the first-line treatment for GH-secreting tumors, TSH-secreting adenomas, and ACTH-secreting tumors. Doctors may also give drugs, such as somatostatin analogs (SSAs) to decrease hormone secretions.
Individuals who had most or all of their pituitary glands removed
Doctors may recommend radiation therapy for tumors that do not respond to medication or surgery. Doctors commonly use one of the following radiation therapies for pituitary microadenomas:
- proton beam treatment
- standard external beam radiotherapy
- stereotactic radiosurgery
Pituitary macroadenomas are 1 cm (10mm) or larger. Because they are bigger masses, they may press on normal pituitary tissue and nearby nerves and
- visual impairment
- a hormonal deficiency
The outlook of pituitary microadenomas depends on whether they secrete hormones or not. Nonfunctioning pituitary microadenomas have an excellent outlook when treated promptly.
Meanwhile, functioning pituitary microadenomas may cause other conditions and complications, which may lead to increased mortality, especially with delays in treatment.
Are pituitary microadenomas serious?
Most pituitary microadenomas are noncancerous, meaning they do not spread to other body parts. They do not make enough hormones to cause symptoms.
Is pituitary microadenoma a brain tumor?
A pituitary microadenoma is a tumor of the pituitary gland, making it an endocrine tumor instead of a brain tumor.
The pituitary gland is small and found at the base of the brain. Attached to the hypothalamus by blood vessels and nerve fibers, it is not part of the brain itself.
Does pituitary microadenoma go away?
What causes microadenomas in the pituitary gland?
It is still unknown what causes microadenomas in the pituitary gland to develop, but certain genetic mutations can cause a person to develop endocrine tumors, including pituitary microadenomas.
Pituitary microadenomas are small, noncancerous tumors that develop in the pituitary gland. Doctors mainly detect them incidentally from imaging tests done for other reasons.
Unlike pituitary macroadenomas, they rarely cause symptoms due to their small size. However, functioning pituitary microadenomas may cause various symptoms depending on the hormones they produce.
The outlook for pituitary microadenomas is generally good with proper treatment. Prompt diagnosis and treatment are essential to prevent complications. Treatment options include medication, surgery, and radiation therapies, depending on the kind of tumor present.