Macroprolactinoma

Macroprolactinoma is a type of pituitary adenoma characterized by the excessive production of prolactin, a hormone responsible for lactation and various other functions. Macroprolactinomas are defined by their size, being larger than 10 mm in diameter, distinguishing them from their smaller counterparts, microprolactinomas. These benign tumors can have significant effects on the body due to the high levels of prolactin they produce, as well as their potential to compress surrounding brain structures as they grow.

Symptoms

The symptoms of macroprolactinoma can vary depending on the tumor's size and the levels of prolactin produced. Common symptoms include:

• Galactorrhea - the production of breast milk in individuals not breastfeeding
• Amenorrhea - the absence of menstrual periods in women
• Infertility in both men and women
• Erectile dysfunction in men
• Visual disturbances due to the compression of the optic chiasm
• Headaches and other neurological symptoms due to the tumor's pressure on surrounding brain tissues

Diagnosis

Diagnosis of macroprolactinoma typically involves a combination of:

• Blood tests to measure prolactin levels
• Magnetic resonance imaging (MRI) to visualize the size and extent of the tumor
• Visual field testing if there is suspicion of optic chiasm compression

Treatment

Treatment options for macroprolactinoma include:

• Dopamine agonists such as cabergoline and bromocriptine, which are effective in reducing prolactin levels and shrinking the tumor in most patients
• Surgery may be considered if the tumor does not respond to medication, or if there is a need for rapid reduction in tumor size due to optic chiasm compression
• Radiation therapy is another option, though less commonly used, and typically reserved for tumors that are resistant to both medical and surgical treatments

Prognosis

The prognosis for individuals with macroprolactinoma is generally good, especially with early diagnosis and treatment. Most patients respond well to dopamine agonists, which can control prolactin levels and reduce tumor size. However, long-term follow-up is often necessary to monitor for potential tumor regrowth or the development of pituitary hormone deficiencies.