A pituitary incidentaloma refers to a mass or lesion found within the pituitary gland that is discovered unexpectedly during an imaging scan. These scans are typically performed for reasons unrelated to the pituitary gland itself, such as investigating headaches or head injuries. Most pituitary incidentalomas are noncancerous growths, often called pituitary adenomas, and they frequently remain small and benign, not causing any symptoms.
Unpacking the Incidentaloma
These masses are often found during head imaging scans, such as CT or MRI, performed for unrelated reasons like chronic headaches or head trauma. They are relatively common, appearing in approximately 10% to 20% of the population.
The pituitary gland, often called the “master gland,” is a small, pea-sized organ at the base of the brain. Despite its size, it produces and regulates numerous hormones controlling bodily functions like growth, blood pressure, and reproduction.
Determining the Nature of the Incidentaloma
Once a pituitary incidentaloma is identified, a detailed diagnostic workup begins to characterize the mass. This typically involves a dedicated pituitary MRI with contrast, which provides high-resolution images to assess the lesion’s size, location, and relationship to surrounding structures, such as the optic nerves. Lesions smaller than 1 centimeter are called microadenomas, while those 1 centimeter or larger are termed macroadenomas.
Blood tests check for hormone levels to determine if the incidentaloma is “functional,” meaning it produces excessive hormones. These tests include prolactin, growth hormone (GH), and ACTH, among others. Elevated levels can indicate specific conditions like prolactinoma, Cushing’s syndrome, or acromegaly.
For larger incidentalomas, or those near the optic nerves, a visual field test or ophthalmological examination is often recommended. A growing mass can compress the optic chiasm, leading to vision changes.
Management Options
Management of a pituitary incidentaloma depends on its characteristics, including size, hormonal activity, and whether it causes symptoms. For many non-functional and asymptomatic incidentalomas, particularly microadenomas, watchful waiting is the most common approach. This involves regular follow-up with clinical assessments, repeat imaging, and hormone level checks to monitor for any changes.
If the incidentaloma is a functional tumor, medical therapy may be the first line of treatment. For example, prolactinomas, which produce excess prolactin, often respond well to specific medications that reduce prolactin levels and may shrink the tumor.
Surgical intervention, typically transsphenoidal surgery, is considered for tumors that cause symptoms, show significant growth, or are hormone-producing but do not respond to medication. This surgical approach involves removing the tumor through the nose or upper lip. Radiation therapy may be another option, sometimes used when surgery is not feasible or fails to remove the entire tumor.
Living with a Pituitary Incidentaloma
Individuals diagnosed with a pituitary incidentaloma typically require ongoing follow-up with an endocrinologist. This involves regular monitoring, including MRI scans and blood tests, with frequency varying based on the incidentaloma’s size and behavior.
It is important to be aware of potential symptoms that could develop, such as new or worsening headaches, changes in vision, or signs of hormone imbalance like unexpected weight changes, fatigue, or reproductive issues. Prompt medical attention should be sought if any new or concerning symptoms arise. The prognosis for most pituitary incidentalomas is generally favorable, as many remain stable and benign, allowing individuals to lead normal lives with appropriate monitoring and, when necessary, treatment.