What is the Difference Between Functioning and Nonfunctioning Pituitary Adenoma

Functioning and nonfunctioning pituitary adenoma are two types of pituitary adenoma, a benign tumor that occurs on the pituitary gland. About 1 in 10 people will normally develop a pituitary adenoma in their lifetime. Unlike other cancers, it does not spread to the other parts of the body. Doctors categorize pituitary adenomas into functioning and nonfunctioning pituitary adenomas based on whether or not they produce extra hormones.

The key difference between functioning and nonfunctioning pituitary adenoma is the secretion of hormones. Functioning pituitary adenoma secretes harmful hormones while nonfunctioning pituitary adenoma does not secrete harmful hormones.

CONTENTS

1. Overview and Key Difference
2. What is Functioning Pituitary Adenoma
3. What is Nonfunctioning Pituitary Adenoma
4. Similarities Between Functioning and Nonfunctioning Pituitary Adenoma
5. Functioning vs Nonfunctioning Pituitary Adenoma in Tabular Form
6. Summary – Functioning vs Nonfunctioning Pituitary Adenoma
7. FAQ – Functioning and Nonfunctioning Pituitary Adenoma

What is Functioning Pituitary Adenoma?

A functioning or secreting pituitary adenoma is a type of pituitary adenoma that releases excess hormones. Functioning pituitary adenomas can cause several different symptoms depending on which pituitary hormones they release, such as male and female infertility, milky discharge from the nipples when not pregnant, acromegaly, gigantism, high blood pressure, muscle weakness, easy bruising stretch marks, osteoporosis, compression fractures, type two diabetes mellitus, rapid heart rate, unexplained weight loss, loose stools, sweating, hand tremors, anxiety, irregular menstruation, and ovarian hyperstimulation syndrome.

Figure 01: Pituitary Tumor

Functioning pituitary adenoma can be diagnosed through family history, physical symptom evaluation, and hormone testing. Furthermore, treatment options for functioning pituitary adenoma include dopamine agonist therapy medications, such as cabergoline or bromocriptine, stereotactic radiosurgery, and surgery.

What is Nonfunctioning Pituitary Adenoma?

Nonfunctioning pituitary adenoma is a type of pituitary adenoma that does not secrete harmful hormones. However, it can also cause symptoms due to tumor growth that creates pressure on the pituitary gland and on the structures near the pituitary. The symptoms of nonfunctioning pituitary adenoma may include hypopituitarism, nausea and vomiting, loss of appetite, weight loss, fatigue, slow or incoherent thinking, dizziness, joint pains, infertility, and irregular or non-existent menstruation in women, impotence and loss of body and facial hair in men, diminished or non-existent sex drive, headache, loss of vision which could involve the loss of peripheral vision or decreased acuity in one or both eyes and double vision.

Figure 02: Nonfunctioning Pituitary Adenoma

Nonfunctioning pituitary adenoma can be diagnosed through family history, physical symptoms evaluation, and imaging tests like MRI, CT scan, and eye examination. Furthermore, treatment options for nonfunctioning pituitary adenoma include medicines to alleviate symptoms, endoscopic pituitary surgery, and gamma knife radiosurgery.

Similarities Between Functioning and Nonfunctioning Pituitary Adenoma

• Functioning and nonfunctioning pituitary adenoma are two types of pituitary adenoma.
• Both types are caused by DNA mutations.
• Both types can be diagnosed through family history and physical examination.
• They can be treated through medications and surgery.

Difference Between Functioning and Nonfunctioning Pituitary Adenoma

Definition

• A pituitary adenoma that secretes hormones is called a functioning pituitary adenoma.
• A pituitary adenoma that does not secrete hormones is called a nonfunctioning pituitary adenoma.

Symptoms

• Symptoms of functioning pituitary adenoma include Cushing syndrome, acromegaly, galactorrhea, hyperprolactinemia, and reproductive problems.
• Symptoms of nonfunctioning pituitary adenoma include hypopituitarism, headaches, vision problems, fatigue, weakness, weight gain or loss, changes in the sex drive, or infertility.

Diagnosis

• Functioning pituitary adenoma can be diagnosed through family history, physical symptoms evaluation, blood tests, and genetic testing.
• Nonfunctioning pituitary adenoma can be diagnosed through family history, physical symptoms evaluation, imaging testing like CT scan, MRI, and genetic testing.

Treatment

• Functioning pituitary adenoma can be treated with dopamine agonist therapy medications, such as cabergoline or bromocriptine, stereotactic radiosurgery, and surgery.
• Nonfunctioning pituitary adenoma can be treated with medications to alleviate symptoms, endoscopic pituitary surgery, and gamma knife radiosurgery.

The following table summarizes the difference between functioning and nonfunctioning pituitary adenoma.

Summary – Functioning vs Nonfunctioning Pituitary Adenoma

A pituitary adenoma is a benign tumor of the pituitary gland. Functioning and nonfunctioning pituitary adenoma are two types of pituitary adenoma. Functioning pituitary adenoma makes harmful hormones, while nonfunctioning pituitary does not make harmful hormones. This is the basic difference between functioning and nonfunctioning pituitary adenoma.

FAQ: Functioning and Nonfunctioning Pituitary Adenoma

1. What are the most common functioning pituitary tumor?

• There are different types of functioning pituitary adenomas, such as prolactinomas, somatotroph, corticotroph, thyrotrophin, and gonadotroph adenomas. They can cause complex clinical symptoms and require prompt treatment like transsphenoidal surgery, medical therapy, and radiation to reduce associated morbidity and mortality.

2. What is the difference between a prolactinoma and a nonfunctioning pituitary adenoma?

• Prolactinoma is a type of functioning pituitary adenoma that secretes harmful hormones. Prolactinomas typically cause hormone-related symptoms, like menstrual changes and decreased sex drive. Non-functioning pituitary adenoma does not release harmful hormones but still causes symptoms due to tumours pressing on the pituitary gland or nearby structures such as vision problems.

3. What are the symptoms of a nonfunctioning pituitary adenoma?

• The symptoms of nonfunctioning pituitary adenoma include nausea and vomiting, loss of appetite, weight loss, fatigue, decreased energy, slow or incoherent thinking, headache, loss of vision, and double vision.

4. What is a nonfunctional macroadenoma?

• Most nonfunctioning pituitary tumors grow large enough to cause local symptoms such as vision problems or headaches, lower levels of pituitary hormones. These adenomas are larger than 10 millimeters.

5. What is the life expectancy of a nonfunctioning pituitary adenoma?

• For most people, treatment such as medications, endoscopic pituitary surgery and gamma knife radiosurgery can control the tumour give a normal lifespan. But people may have to deal with its consequences, such as vision issues.

Reference:

1. “Non Functioning Pituitary Adenomas.” Barrow Neurological Institute.
2. “Pituitary Adenomas.” UCLA Health.

Image Courtesy:

1. “1614 Pituitary Tumor-02” By OpenStax College – Anatomy & Physiology, Connexions Web site (CC BY 3.0) via Commons Wikimedia
2. “Coronal section of non-functioning pituitary adenoma” By Cerevisae – Own work (CC BY-SA 4.0) via Commons Wikimedia

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