Multifocal fibrosclerosis (related to IgG4-related disease)

Multifocal fibrosclerosis is an older term for a condition in which fibrous, scar-like inflammation develops in several places in the body at once, such as the tissue behind the abdomen (retroperitoneal fibrosis), around the eye socket, the thyroid, and the tissue in the chest. Research describes many cases once labeled multifocal fibrosclerosis as now falling within the broader spectrum of IgG4-related disease, an immune-mediated condition marked by tissue infiltration with IgG4-positive plasma cells and progressive fibrosis, though not every case of fibrosclerosis has this IgG4 pattern. Idiopathic retroperitoneal fibrosis, the most studied example, accounts for the large majority of retroperitoneal fibrosis cases and is generally responsive to immune-suppressing treatment such as corticosteroids, which supports an immune-mediated understanding of the disease.

Because the condition is rare and the terminology has shifted substantially as understanding of IgG4-related disease has developed, precise prevalence figures for multifocal fibrosclerosis specifically are not well established in the literature. Symptoms depend on where the fibrous inflammation sits, ranging from back or flank pain and kidney effects to eye changes, neck swelling, or chest symptoms.

Common signs

Symptoms depend on where the fibrous inflammation sits. It can cause back or flank pain and effects on the kidneys or ureters when behind the abdomen, eye bulging or vision changes around the eye socket, neck swelling or thyroid changes, and chest symptoms when the chest is involved. Some people have leg swelling from compressed veins or no symptoms until it turns up incidentally on imaging.

This is a plain-language summary for orientation, not a diagnosis. Mechanisms are described as current understanding, not settled fact. Work with your own clinician for your care.