Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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May 30, 2019
Lymphocytic Hypophysitis
- Background
- Lymphocytic hypophysitis (LH), also known as autoimmune hypophysitis, is characterized by diffuse lymphocyte (CD4+ T-cell predominant) infiltration of the pituitary gland with a 9:1 female to male predominance, most commonly occurring during the third trimester of pregnancy or the early postpartum period.
- LH is sub-classified based on pituitary segment involvement:
- Anterior pituitary: lymphocytic adenohypophysitis (LAH)
Posterior pituitary: lymphocytic infundibular neurohypophysitis (LINH) - Mixed: lymphocytic infundibular panhypophysitis (LPH)
LH is associated with autoimmune diseases such as Sjogren’s syndrome, thyroiditis, systemic lupus erythematosis, and Addison’s disease in up to 30% of cases.
- Anterior pituitary: lymphocytic adenohypophysitis (LAH)
- Clinical Presentation
- Commonly present with compressive sellar symptoms, including headache and visual disturbances from optic chiasm or cranial nerves III, IV, or VI compression.
- Hypopituitarism is the other main presenting symptom. LINH is specifically associated with diabetes insipidus, while LAH is associated with anterior pituitary abnormalities. LPH is characterized by a combination of both.
- Key Diagnostic Features
- CT demonstrates a homogeneously enhancing pituitary region mass with thickened pituitary stalk.
- MRI is the preferred modality and demonstrates a thickened infundibulum with heterogeneous T1 isointensity and T2 iso/hypointensity with intense homogeneous enhancement.
- May be associated with sphenoid sinus mucosal thickening and loss of the posterior pituitary T1 “bright spot.”
- Differential Diagnosis
- Pituitary macroadenoma – Enlargement/remodeling of the sella turcica is typically only seen with macroadenoma, while isolated stalk thickening is not. Additionally, macroadenomas are typically T2 isointense to grey matter, while LH can be hypointense. The Gutenberg score can further aid in differentiating the two pathologies.
- Pituitary hyperplasia – No infundibular thickening.
- Infectious and non-infectious granulomatous hypophysitis – Presence of systemic illness such as sarcoidosis, cocci, or tuberculosis.
- Medication induced – Usage of Ipilimumab, most commonly in the setting of metastatic melanoma.
- Metastasis/lymphoma – Rarely would present as an isolated focus of the pituitary infundibulum.
- IgG4 – Pituitary gland enlargement with or without infundibulum enlargement and hypertrophic pachymeningitis.
- Treatment
- Treatment is conservative with high-dose pulse corticosteroids and hormone replacement, which can be long-term. Desmopressin is indicated in the setting of diabetes insipidus.
- In refractory cases, immunosuppressant therapy such as methotrexate, azathioprine, and cyclosporine can be utilized.
Surgical resection can be performed in the setting of intractable headaches and visual loss after failed medical management.
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