A prolactinoma is a noncancerous tumor (adenoma) that develops in the pituitary gland, a small structure at the base of the brain. This tumor causes the overproduction of prolactin, which disrupts normal reproductive function in both men and women. First-line treatment involves dopamine agonists (such as cabergoline or bromocriptine), which shrink the tumor and normalize prolactin levels. However, when medication fails or is not tolerated, surgery becomes a necessary option.
When Surgery Becomes the Primary Treatment
The decision to move to surgery is made when dopamine agonists fail to meet treatment goals or when the tumor presents an immediate physical threat. One common scenario is drug intolerance, where patients experience severe side effects (such as nausea, dizziness, or fatigue) that make long-term adherence impossible. Surgery offers a viable path to remission for patients who must discontinue medication due to adverse effects.
Another major indication is drug resistance, occurring when medication fails to normalize prolactin levels or significantly shrink the tumor mass. Resistance is more frequent with larger tumors (macroadenomas). If a large prolactinoma does not respond to maximal medical therapy, continued growth can lead to mass effects that compromise neurological function.
The most urgent reason for surgical intervention is a mass effect, particularly compression of the optic chiasm, leading to vision impairment. While medication often resolves these issues, rapid or worsening vision loss requires immediate tumor debulking. Surgery may also be considered upfront for specific tumor types, such as those that are largely cystic or have experienced pituitary apoplexy, as these features limit standard medical treatment effectiveness. For women with large tumors planning a pregnancy, surgery may be recommended beforehand to reduce the risk of tumor growth during gestation.
Pre-Surgical Evaluation and Planning
A comprehensive evaluation ensures the operation is safe and precisely planned. Detailed imaging, typically a high-resolution MRI scan, maps the exact size, location, and extent of the tumor, including any invasion into surrounding structures like the cavernous sinus. This imaging is crucial for the neurosurgeon to determine the most effective surgical approach and estimate the chances of complete tumor removal.
Hormonal baseline testing assesses the function of the pituitary gland and checks all other hormone levels it controls. This identifies pre-existing hormonal deficiencies (hypopituitarism) that may require replacement therapy before or immediately after the procedure. For patients with large tumors, formal visual field testing is mandatory to establish a baseline of visual function.
The patient consults with both the neurosurgeon and the endocrinologist to discuss expected outcomes and potential risks. Risks such as CSF leakage, new or worsening hormonal deficiencies, and bleeding are thoroughly reviewed. This planning phase ensures the surgical team is prepared for the operation and subsequent management of the patient’s hormonal and neurological status.
The Surgical Experience
The most common procedure for removing a prolactinoma is the transsphenoidal approach, a minimally invasive technique that avoids open brain surgery. “Transsphenoidal” means “through the sphenoid sinus,” the air-filled cavity behind the nose. The procedure is often performed by a neurosurgeon and an ENT surgeon, who navigate together to the pituitary gland.
The surgeon accesses the tumor by passing instruments through the nasal cavity and the sphenoid sinus, eliminating the need for an external incision. Using either a microscope or an endoscope, the surgeon gains a magnified view of the surgical field. The objective is to meticulously remove the tumor while preserving the surrounding healthy pituitary tissue and nearby nerves.
The typical duration for a transsphenoidal procedure is approximately two to three hours. While this method is suitable for most prolactinomas, a craniotomy (temporary skull removal) is reserved for very large or complex tumors inaccessible through the nasal route. The success of achieving hormonal remission depends on the surgeon’s experience and the tumor’s size, with small tumors having a higher chance of complete removal.
Hospital Stay, Recovery, and Follow-Up
Immediately following the procedure, patients are transferred to a specialized unit for close monitoring during the first 24 hours. The medical team checks for complications, including changes in vision, excessive urination (indicating a water balance issue), or signs of a CSF leak. The typical hospital stay for transsphenoidal surgery ranges from two to five days.
Patients commonly experience transient side effects during initial recovery, such as nasal congestion, a mild headache, and a diminished sense of smell. Activity restrictions are imposed for several weeks to allow the surgical site to heal fully. These restrictions include avoiding strenuous activity, heavy lifting, and forcefully blowing the nose. Full recovery and return to normal activities usually takes between four and six weeks.
Long-term management involves routine follow-up with the endocrinologist and neurosurgeon to ensure the tumor has not recurred and that hormonal balance is maintained. This includes periodic blood tests (for prolactin and other pituitary hormones) and follow-up MRI scans performed a few months after surgery. If pituitary function was affected, patients may require temporary or permanent hormone replacement therapy, adjusted based on ongoing blood work. Remission rates are favorable, especially for smaller tumors, requiring long-term monitoring.