| Autoimmune Hypophysitis |
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Prepared by: Daniela Cihakova MD, PhD Definition: It is an inflammatory process, possibly autoimmune, involving mainly the front part of the pituitary gland. Description: The pituitary gland is a bean-shaped gland located at the base of the brain in the midline. It measures around 1cm. The anterior pituitary releases growth hormone, thyroid stimulating hormone, ACTH - the adrenocorticotropic hormone, follicle-stimulating hormone (FSH), luteinizing hormone (LH). The posterior pituitary gland releases two hormones, oxytocin, and antidiuretic hormone. Symptoms: The symptoms are nonspecific and mimick adenoma, a type of tumor. Symptoms are local, related to growth of pituitary gland due to inflammation. The patient can experience loss of vision in half of the visual field (hemianopia) and headache. Other symptoms are endocrine. Due to destruction of the anterior pituitary gland, the levels of some hormones produce by the pituitary can be low – usually ACTH hormone or occasionally other or all pituitary hormones. This condition is called hypopituitarism. However, many patients have only increased prolactin level. Diagnosis: MRI shows increase size of pituitary gland, which is very difficult to distinguish from pituitary adenomas, a type of tumor.. Incidence: Lymphocytic hypophisitis is a very rare disease; to date around 100 patients have been reported in literature. They are predominantly women; the female-to-male ratio being 8.5: 1. There is a strong predilection of lymphocytic hypophysitis to occur during or after pregnancy. Treatment: Untreated hypophisitis may end by a spontaneous recovery or the destruction of pituitary gland can continue and lead to hypopituitarism. Corticosteroids are occasionally used. Adequate hormone replacement therapy and follow-up is important. Transsphenoidal surgery is sometimes provided if there are symptoms of local compression or for biopsy to distinguish hypophisitis from tumor, but the prognosis of a Pathogenesis: There are certain pieces of evidence that lymphocytic hypophisitis is an autoimmune disease: Circumstantial evidence:
Indirect evidence: Mice used as murine model of autoimmune thyroid disease [MRL-lpr/lpr] immunized with murine, rat, porcine or human pituitary glands develop inflammation in the hypophysis. |
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Links to other Resources: pathology2.jhu.edu/hypophysitis |
