General description

IgG4-related disease (IgG4-RD) is a disease of unknown cause in which various organs throughout the body, including the pancreas, salivary glands, lacrimal glands, kidneys, blood vessels, and retroperitoneum, are involved, and is believed to be related to immune abnormality.

One of the characteristic immune abnormalities seen in many patients is high levels of serum IgG4 and the infiltration of many IgG4-producing cells in the affected organs.

While there is no clear gender difference in patients with involvement of the salivary or lacrimal glands, it is generally more common in older men with involvement of the pancreas, kidneys, or blood vessels.

In the central nervous system, involvement of the pituitary-hypothalamic axis is common in IgG4-related disease, often accompanied by Hypertrophic pachymeningitis. This condition is characterized by thickening and inflammation of the dura mater, which can lead to various neurological symptoms depending on the location of the affected meninges.

Involvement of the pituitary gland and stalk in IgG4-related disease is termed IgG4-related hypophysitis. Anterior pituitary lobe involvement can manifest clinically with decreased libido, erectile dysfunction, hypothyroidism, and hypoadrenalism. Conversely, if the posterior pituitary lobe or pituitary stalk is affected, diabetes insipidus may be observed.

Radiographic features

Hypophysitis

Imaging studies demonstrate enlargement of the pituitary gland and stalk, with hyperintense signal on T2-weighted imaging sequences and homogeneous contrast enhancement.

Pachymeningitis

Imaging studies show dural thickening with T2WI hypointensity and contrast effect. See also Hypertrophic pachymeningitis.