Pituitary Tumors

What Patients and Referring Providers Need to Know

"We found something on your MRI near your pituitary gland." It sounds alarming, and the word tumor sounds scary. But the truth is that pituitary tumors are common, almost always benign, and treated with one of three very different strategies depending on what type they are — watching, medication, or surgery. Knowing which category a given tumor falls into is very important.

This page walks through what the pituitary gland does, the different types of pituitary tumors, how we decide between surveillance, medical therapy, and surgery, and — for the patients who do need an operation — exactly what that surgery and recovery look like.

What Does the Pituitary Gland Do?

The pituitary is a pea-sized gland that sits at the base of the brain, cradled in a small bony pocket called the sella turcica, directly beneath the optic chiasm — the point where the optic nerves cross on their way to the brain. It's often called the "master gland" because it directs so many of the body's other hormone systems: the thyroid, the adrenal glands, growth, reproduction, and lactation all take their cues from hormones the pituitary releases.

A pituitary tumor is almost always a benign growth called an adenoma, arising from the gland's own hormone-producing cells. What matters clinically isn't whether it's "cancer" — it essentially never is — but two other questions: does it make extra hormone, and is it big enough to press on the structures around it, particularly the optic chiasm above it.

The Different Types

Pituitary adenomas are classified two ways: by size and by whether they secrete hormone.

• Microadenomas are smaller than 10 mm and rarely cause mass effect; if they cause problems, it's almost always because they're overproducing a hormone (normally cortisol).
• Macroadenomas are 10 mm or larger and are the ones more likely to press on the optic chiasm, causing the classic pituitary tumor visual complaint — loss of peripheral vision on both sides (bitemporal hemianopsia) — or to cause headaches and deficiencies in other pituitary hormones simply from crowding the normal gland.

By function, the tumor types are:

• Nonfunctioning adenomas — the most common type overall. These don't secrete active hormone and are often found incidentally on an MRI or CT ordered for an unrelated reason (a "pituitary incidentaloma"). Symptoms, when present, come entirely from size and mass effect, not hormone excess.
• Prolactinomas — the most common functioning type, secreting prolactin. In women this often presents relatively early with irregular periods, infertility, or unexpected breast milk production (galactorrhea), which is why prolactinomas are sometimes caught as microadenomas. In men, symptoms (low testosterone, erectile dysfunction, low libido) are less specific and often overlooked, so prolactinomas in men are more often found as larger macroadenomas.
• Growth hormone–secreting adenomas — cause acromegaly in adults: gradually enlarging hands, feet, and facial features, joint pain, sleep apnea, and an increased risk of diabetes and cardiovascular disease. In children whose growth plates haven't closed, the same tumor causes gigantism.
• ACTH-secreting adenomas — cause Cushing's disease, from excess cortisol: weight gain (especially central), thin skin, easy bruising, muscle weakness, high blood pressure, and mood changes.
• TSH-secreting and gonadotroph-secreting adenomas — both uncommon. TSH-secreting tumors cause a paradoxical hyperthyroidism; gonadotroph-secreting tumors usually make hormone too inefficiently to cause a clear clinical syndrome and often behave, and are treated, like nonfunctioning adenomas.

Three Paths: Watch, Treat with Medication, or Operate

Not every pituitary tumor needs surgery.

How the Surgery Is Done

Endoscopic transsphenoidal surgery is performed under general anesthesia, typically takes two hours, and — unlike a craniotomy — involves no incision on the head or face at all. I work with an ENT colleague for the nasal portion of the approach on most cases.

1. Setup. Image-guidance (neuronavigation, built from the patient's preoperative MRI) is registered to the patient so instrument position can be tracked in real time relative to the tumor and the surrounding carotid arteries and optic nerves.
2. Nasal approach. Working through the nostril with a high-definition endoscope, we advance through the nasal cavity to the back wall of the sphenoid sinus — no external incision is needed.
3. Opening the sella. The thin bone of the sphenoid sinus and the floor of the sella turcica is removed to expose the covering of the pituitary gland and tumor.
4. Tumor removal. Working through this corridor with fine instruments, the tumor is removed and separated from the normal gland, which is preserved whenever possible.
5. Closure. The skull base is reconstructed, often with a small graft of fat or fascia (occasionally taken through a tiny abdominal incision) and this is supported with a dural onlay graft, to prevent a cerebrospinal fluid (CSF) leak. I then rebuild the anterior wall of the sella (the bone) with a MedPor TSI implant. A temporary lumbar drain is sometimes (very rarely) placed for larger tumors with a higher leak risk.

Recovery: What to Expect

Vision improvement, when the tumor was compressing the optic chiasm, is often noticeable within days. Hormone levels are checked closely in the first days after surgery, both to confirm a hormone-secreting tumor has been adequately treated and to watch for any temporary drop in normal pituitary function.

Risks and Complications

• Diabetes insipidus — temporary disruption of the gland's water-regulating hormone (ADH), causing excess thirst and urination; common in the first days after surgery and usually resolves on its own, though a small percentage of patients need long-term desmopressin
• CSF leak — leakage of spinal fluid through the surgical corridor, occurring in roughly 1 in 100 cases; usually managed with a brief period of bed rest or a lumbar drain, occasionally requiring a return to the operating room for repair
• Hypopituitarism — reduced function of the remaining normal gland, more common with larger tumors, which may require hormone replacement (thyroid, cortisol, sex hormones) either temporarily or long-term
• Vision changes — injury to the optic nerve or chiasm is uncommon but is the most serious potential complication given their proximity to the tumor
• Meningitis, bleeding, or injury to the carotid artery — rare, given the corridor's proximity to these structures, which is why image guidance and, often, a two-surgeon team are standard
• Nasal symptoms — temporary congestion, crusting, or reduced sense of smell; persistent smell loss is uncommon

A Note to Patients

If you just found out you have a pituitary tumor give our office a call (678-312-2700). Most of these tumors are benign, many never need anything more than periodic imaging, and even the ones that need treatment respond very well to either medication or a well-established, minimally invasive surgery. The goal of that first conversation is simply to figure out which of the three categories your tumor falls into — and from there, the path forward is usually a lot clearer than the words on the radiology report made it sound.