What is Lymphocytic Hypophysitis?

An autoimmune inflammation of the pituitary gland. The immune system attacks the pituitary, causing it to swell and potentially leading to hormone deficiencies.

Who gets it?

• Women: Especially during late pregnancy or shortly after delivery.
• Autoimmune Associations: People with other autoimmune diseases (thyroiditis, Type 1 diabetes).
• Checkpoint Inhibitor Immunotherapy: Cancer drugs (like Pembrolizumab, Nivolumab) can trigger it.

Symptoms:

• Headaches.
• Vision Problems (from pituitary swelling compressing optic nerves).
• Hormone Deficiencies: Most commonly ACTH (causing adrenal insufficiency) and TSH.
• Diabetes Insipidus (if posterior pituitary is involved).

Diagnosis:

• MRI: Enlarged, symmetrically swollen pituitary (looks like a tumor!).
• Hormone Tests: Low cortisol, thyroid, etc.
• Biopsy (Rarely Done): Shows lymphocytic infiltration.

Challenge:

It looks just like a pituitary tumor on MRI. Many patients undergo unnecessary surgery before the diagnosis is made.

Treatment:

• Observation: Some cases resolve on their own.
• High-Dose Steroids (Prednisone): Can shrink the inflammation.
• Hormone Replacement: For any deficiencies (hydrocortisone, levothyroxine, desmopressin).