Pituitary Tumor

Pituitary tumors (pituitary adenomas) are growths in the pituitary gland at the base of the brain. When large enough, they can compress the optic chiasm (where the optic nerves cross), causing a characteristic pattern of vision loss affecting peripheral vision in both eyes.

Understanding Pituitary Tumors

The pituitary gland sits in a bony pocket (sella turcica) just below the optic chiasm. When a tumor grows upward, it presses on the crossing fibers in the chiasm. These fibers carry information from the temporal (outer) visual fields of each eye, which is why peripheral vision is lost on both sides.

Symptoms

Visual Symptoms

Bitemporal hemianopia

• Loss of outer (peripheral) visual fields in both eyes
• May not notice initially—central vision preserved
• Difficulty with peripheral awareness

Other visual symptoms:

• Blurred vision
• Double vision (if nerves to eye muscles affected)
• Complete vision loss in one eye (rare, severe cases)

Hormonal Symptoms

From hormone-secreting tumors:

• Prolactinoma: irregular periods, breast discharge, infertility
• Growth hormone tumor: enlarged hands/feet, facial changes
• ACTH tumor (Cushing's): weight gain, diabetes, high blood pressure
• TSH tumor: hyperthyroid symptoms

From hormone deficiency (large tumors):

• Fatigue
• Low libido
• Cold intolerance
• Menstrual changes

Other Symptoms

• Headache
• Fatigue
• Sometimes no symptoms (incidental finding)

Types of Pituitary Tumors

By Size

• Microadenoma: Less than 10mm—rarely causes visual problems
• Macroadenoma: 10mm or larger—may compress optic chiasm

By Function

• Non-functioning: Don't produce hormones—discovered by mass effect
• Functioning: Produce excess hormones—symptoms depend on hormone type

Diagnosis

Eye Examination

• Visual field testing—shows characteristic bitemporal pattern
• Visual acuity
• Color vision testing
• Optic nerve assessment—may show optic atrophy

Imaging

MRI brain with pituitary protocol

• Best test for visualizing pituitary tumors
• Shows size and relationship to optic chiasm
• Characterizes tumor type

Hormonal Testing

• Complete pituitary hormone panel
• Specific tests based on suspected tumor type
• Important for treatment planning

Treatment

Medications

For prolactinomas (most common):

• Cabergoline or bromocriptine
• Often shrink tumor effectively
• May restore vision without surgery

Surgery

Transsphenoidal surgery

• Through nose/sinuses to reach pituitary
• Minimally invasive
• Gold standard for most non-prolactinomas

Craniotomy

• Through skull—for large or complex tumors
• Less common approach

Radiation

• For residual or recurrent tumors
• Stereotactic radiosurgery (focused)
• Conventional radiation (fractionated)

Hormone Replacement

• May be needed after surgery
• Lifelong monitoring of pituitary function

Visual Prognosis

Factors Affecting Recovery

• Duration of vision loss before treatment
• Severity of visual field defects
• Success of tumor removal/shrinkage
• Presence of optic atrophy

Expected Outcomes

• Many patients see visual field improvement
• Improvement may occur within weeks of treatment
• Some permanent loss if optic atrophy present
• Regular monitoring needed

Living with Pituitary Tumors

Driving

• Visual field requirements must be met
• May need to wait until stable after treatment
• Discuss with your doctor

Follow-up

• Regular MRI scans
• Visual field testing
• Hormonal assessments
• Lifelong monitoring usually needed

Frequently Asked Questions

Is a pituitary tumor cancer?

The vast majority of pituitary tumors are benign (not cancer). True pituitary cancer is extremely rare. However, even benign tumors can cause problems by growing and pressing on nearby structures.

Will my vision come back after treatment?

Many patients experience significant improvement in their visual fields after successful treatment, especially if caught early. However, if significant optic nerve damage (atrophy) has occurred, some vision loss may be permanent.

Do I need surgery, or can the tumor be treated with medication?

This depends on the tumor type. Prolactinomas often respond well to medication and may not need surgery. Other tumor types usually require surgery as primary treatment.

How often will I need follow-up?

Initially, follow-up is frequent (every few months) to monitor response to treatment. Once stable, annual or less frequent monitoring may be appropriate. Visual fields, MRI, and hormonal testing are all part of long-term follow-up.

References