Pannus is an abnormal layer of fibrovascular tissue, essentially granulation tissue, that forms in various parts of the body. This abnormal growth can occur in several locations and is often associated with inflammatory conditions.
Where Pannus Can Form:
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Joints: Pannus is commonly found in joints affected by rheumatoid arthritis (RA). In RA, the pannus grows over the joint surface, causing damage to cartilage and bone. [WebMD, Healthline, Elsevier] This growth can lead to significant joint pain and dysfunction. Even in the absence of rheumatoid arthritis or trauma, cervical pannus can develop, sometimes following spine surgery. [NCBI PMC]
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Cornea (Eyes): In dogs, pannus, also known as chronic superficial keratitis, is an immune-mediated condition affecting the cornea, the clear front part of the eye. [VCA Animal Hospitals, ACVO] Certain breeds like German Shepherds, Greyhounds, and Dachshunds are predisposed. [ACVO]
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Prosthetic Heart Valves: Pannus can also form on prosthetic heart valves, potentially leading to valve dysfunction. [NCBI PMC] This is a rare complication, but it can be serious.
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Stomach (Abdominal Wall): An apron-like accumulation of fat over the abdomen is sometimes referred to as "pannus stomach" or "apron belly." This is not the same type of pannus as the fibrovascular tissue found in joints or on the cornea, but rather an accumulation of excess abdominal fat. Weight loss and exercise might help reduce the appearance, but there are no specific targeted treatments. [Medical News Today, Verywell Health]
Understanding Pannus:
While often considered inactive scar tissue, recent research suggests pannus in rheumatoid arthritis possesses more biological activity than previously thought and may play a role in ongoing joint damage. [Elsevier]
The formation of pannus is usually linked to an underlying inflammatory process. The exact mechanisms vary depending on the location.
