Lymphocytic hypophysitis is an uncommon non-neoplastic inflammatory condition that affects the pituitary gland. It is closely related to other inflammatory conditions in the region, namely orbital pseudotumor and Tolosa-Hunt syndrome.
Lymphocytic hypophysitis is seen most frequently in women, with a F:M of ~ 9:1, and often in the postpartum period or the third trimester of pregnancy.
Clinical presentation is varied depends on the part of the pituitary affected and the size of the lesion. Lymphocytic hypophysitis can thus be classified as:
- anterior pituitary: lymphocytic adenohypophysitis
- posterior pituitary: lymphocytic infundibular neurohypophysitis
- diabetes insipidus
- both anterior and posterior pituitary: lymphocytic infundibular panhypophysitis
It is characterized by infiltration of the pituitary stalk with lymphocytes, as the name would suggest. Importantly, there is a paucity of plasma cells or granulomas, differentiating it from IgG4-related hypophysitis and granulomatous hypophysitis (e.g. due to neurosarcoidosis) respectively.
- autoimmune conditions such as
- ipilimumab: monoclonal antibody drug
Coronal CT and multiplanar reconstructions can visualize the pituitary region reasonably well. Lymphocytic hypophysitis appears as an enhancing soft tissue mass involving the pituitary and extending into the suprasellar region.
MRI, as is the case with other pituitary lesions, is the best modality for assessing this condition which appears as a pituitary region mass.
- affected area is isointense with slight signal heterogeneity
- normal posterior pituitary bright spot may be absent
- T1 C+ (Gd)
- can variably enhance, usually homogeneously
- dural enhancement may be present
- infundibulum may be thickened
- hypointensity in parasellar region can be present and may be useful in differentiating from a pituitary adenoma
Treatment and prognosis
Lymphocytic hypophysitis is usually self-limiting and spontaneous recovery can occur. Corticosteroids are sometimes given and deficient hormones can be replaced .
The differential diagnosis is primarily that of other pituitary region masses. Considerations include:
- pituitary adenoma
- macroadenomas are expected to enlarge the sella turcica
- craniopharyngioma (papillary type)
- suprasellar meningioma
- usually follows the cerebral cortex intensity
- pituitary metastasis
- Langerhans cell histiocytosis (LCH)
- IgG4-related hypophysitis
- granulomatous hypophysitis (idiopathic or secondary to systemic illness e.g. sarcoidosis, syphilis, and tuberculosis)
- xanthomatous hypophysitis
- necrotizing hypophysitis