A prolactinoma is a noncancerous growth that develops on the pituitary gland. This pea-sized gland is located at the base of the brain and regulates many of the body’s hormones. A prolactinoma produces an excess amount of prolactin, a hormone primarily involved in breast milk production. While medication is often the initial approach, surgery is an important treatment option for these tumors.
When Surgery is Recommended for a Prolactinoma
Medical therapy, specifically with dopamine agonists like cabergoline or bromocriptine, is the first-line treatment for prolactinomas. These medications are effective in shrinking the tumor and normalizing prolactin levels. However, surgery is considered in several specific situations where medication alone is not sufficient or appropriate.
One primary reason for surgery is when patients experience intolerance to dopamine agonists, enduring severe side effects such as nausea, vomiting, or dizziness. Another indication arises if the medication proves ineffective at lowering prolactin levels or reducing the tumor’s size adequately.
Surgery is also considered for specific tumor characteristics, such as a cystic prolactinoma, which may not respond to medical treatment. In acute situations, like sudden vision loss caused by bleeding into the tumor (known as pituitary apoplexy), immediate surgical intervention can be necessary to relieve pressure on the optic nerves. Patient preference, after discussion of all treatment options, is also a reason for choosing surgery.
The Transsphenoidal Surgical Procedure
The most common surgical method for removing a prolactinoma is endoscopic endonasal transsphenoidal surgery. This minimally invasive procedure involves accessing the pituitary gland through the nasal cavity and the sphenoid sinus, a hollow space located behind the nasal passages. A surgeon uses a thin, flexible tube with a camera and light, called an endoscope, to navigate this pathway without making any external incisions on the face.
The procedure involves a team of specialists, including a neurosurgeon and an ear, nose, and throat (ENT) surgeon. After inserting the endoscope, the surgeon opens the bony wall of the sphenoid sinus that covers the pituitary gland. Small surgical instruments are then passed through this opening to remove the tumor in small pieces. This approach is designed to minimize damage to surrounding brain structures and results in no visible scarring.
While transsphenoidal surgery is preferred, a craniotomy, which involves opening the skull, is a rarer alternative. This more invasive approach is reserved for large or complex tumors that cannot be reached through the nasal passage. Craniotomy allows for a broader view of the tumor and surrounding structures but carries a higher risk of complications compared to the transsphenoidal method.
Recovery and Post-Surgical Care
Following transsphenoidal surgery for a prolactinoma, patients remain in the hospital for one to five days. During this post-operative period, medical staff monitor vital signs and perform blood tests to check hormone levels, sodium balance, and water regulation. Some patients may have nasal packing for a few days to manage bleeding and support healing.
Upon returning home, recovery takes four to eight weeks. Common experiences include nasal congestion, mild headaches, and fatigue. Patients should avoid activities that increase pressure in the head, such as blowing the nose, heavy lifting, or straining during bowel movements, for several weeks to prevent complications like nasal bleeding or cerebrospinal fluid (CSF) leaks.
Regular follow-up appointments are part of post-surgical care. These involve visits with an endocrinologist to monitor prolactin levels and other pituitary hormones, as well as with the neurosurgeon to assess healing and overall recovery. An MRI scan is performed within one to three months after surgery to confirm tumor removal and monitor for any residual tissue.
Surgical Outcomes and Potential Risks
The goal of prolactinoma surgery is to normalize prolactin levels and restore normal pituitary gland function. Success rates vary depending on tumor size, with smaller tumors (microadenomas, less than 10mm) having a higher chance of remission compared to larger tumors (macroadenomas). For microadenomas, successful normalization of prolactin levels can be achieved in 80-90% of cases, while for macroadenomas, this rate ranges from 50-70%.
Despite favorable outcomes, surgical removal of a prolactinoma carries potential risks. One risk is damage to the normal pituitary gland, which could lead to deficiencies in other hormones (hypopituitarism) requiring lifelong hormone replacement therapy. Another complication is a cerebrospinal fluid (CSF) leak, where the fluid surrounding the brain and spinal cord leaks from the nose.
Infections, such as meningitis, are rare but serious risks associated with any surgical procedure involving the brain or its surrounding structures. Damage to nearby blood vessels or nerves is also possible, leading to neurological deficits. Some patients may experience temporary changes in their sense of taste or smell following the procedure.