What is degenerative pannus? A medical overview

September 29, 2025 •

5 min read

Affecting millions, autoimmune diseases can lead to chronic inflammation and, in severe cases, abnormal tissue growth known as pannus. This guide will explore the specific condition of degenerative pannus, detailing its causes, symptoms, and treatment pathways to help you better understand this health issue.

Quick Summary

Degenerative pannus is an abnormal growth of fibrous tissue that results from prolonged inflammation, often associated with autoimmune diseases like rheumatoid arthritis but also linked to trauma and other conditions. It can cause significant joint destruction, pain, and disability if left untreated, affecting joints, the eyes, or even heart valves.

Key Points

Definition: Degenerative pannus is abnormal fibrous tissue growth resulting from chronic inflammation, often distinct from the more cellular, active pannus seen in acute phases of disease.
Underlying Cause: It is most frequently associated with untreated or long-standing autoimmune diseases like rheumatoid arthritis, but can also be caused by trauma or chronic irritation.
Affected Areas: While most commonly affecting joints, pannus can also develop in other areas like the cornea of the eye (corneal pannus) or on prosthetic heart valves.
Symptoms: Symptoms are similar to those of the underlying inflammatory condition and include joint pain, swelling, stiffness, and decreased range of motion, potentially leading to joint deformity.
Diagnosis: Confirmation of pannus and its impact relies on imaging techniques such as MRI, CT scans, and X-rays, which visualize the abnormal tissue and any resulting bone or cartilage damage.
Treatment: Management focuses on controlling the underlying cause with medications like DMARDs and biologics to stop the inflammatory process. Surgical removal may be necessary for severe cases.

What exactly is degenerative pannus?

In medical terms, pannus refers to an abnormal layer of fibrovascular tissue that spreads over a normal bodily structure. The term 'degenerative pannus' often distinguishes it from the more aggressive, inflammatory type of pannus typically seen in the early stages of diseases like rheumatoid arthritis (RA). Degenerative pannus is characterized by a high content of collagen and fibrous tissue, with fewer inflammatory cells, making it a more chronic, scar-like manifestation of long-term inflammation. While the more aggressive, active pannus is rich with inflammatory cells that actively attack tissue, the degenerative form represents a later, less cellular stage. This doesn't mean it is harmless; this fibrotic tissue can still cause significant damage by invading and destroying cartilage and bone over time.

Degenerative pannus in joints: A consequence of chronic inflammation

The most well-known context for pannus is in the joints of individuals with rheumatoid arthritis, where it is a hallmark sign of the disease. In RA, the immune system mistakenly attacks the synovium, the soft tissue lining the joints. This causes the synovium to thicken and proliferate uncontrollably, forming pannus. While the initial stage is highly inflammatory, over time, chronic, untreated inflammation can lead to a more degenerative or fibrotic form of pannus.

Causes of pannus formation

Rheumatoid Arthritis (RA): This is the most common cause of pannus formation. The autoimmune response triggers a cascade of inflammatory events that result in the thickening and overgrowth of the synovial membrane.
Other Inflammatory Arthropathies: Conditions such as psoriatic arthritis can also cause synovial inflammation and subsequent pannus formation, though less commonly than RA.
Trauma: In certain cases, especially concerning the cervical spine, severe trauma can lead to instability and the formation of a pannus-like mass, known as odontoid pannus, even without an underlying autoimmune condition.
Chronic Edema: As seen in the eye, chronic swelling from conditions like glaucoma can lead to the formation of a degenerative pannus in the cornea.

Recognizing the symptoms

The symptoms of pannus formation in a joint often mirror the symptoms of the underlying inflammatory arthritis. These can include:

Persistent and increasing joint pain
Swelling and tenderness, often feeling spongy or boggy to the touch
Stiffness, especially in the morning or after periods of rest
Decreased range of motion
Visible joint deformity as the pannus invades and destroys cartilage and bone
In specific cases like cervical (odontoid) pannus, severe symptoms can arise from spinal cord compression, such as neck pain, numbness, and gait abnormalities.

Degenerative pannus beyond the joints

The term pannus is not exclusive to joints; it refers to abnormal tissue growth that covers and invades normal structures elsewhere in the body.

Corneal pannus

In the eye, pannus is the ingrowth of fibrous and vascular tissue onto the cornea. This condition, known as chronic superficial keratitis, can be inflammatory or degenerative. Degenerative corneal pannus, characterized by minimal inflammation, can result from chronic epithelial edema or severe contact lens wear and can lead to scarring and vision impairment.

Prosthetic heart valve pannus

In some cases, fibrous tissue can slowly grow over the rings of prosthetic heart valves, a condition also referred to as pannus. This can obstruct the valve's function, narrow the blood flow, and potentially lead to secondary clot formation, requiring surgical intervention.

Diagnosing pannus

For joint-related pannus, diagnosis typically involves a combination of a physical examination and advanced imaging. A physician will assess the affected joint for signs of swelling, tenderness, and deformity. To confirm the presence of pannus and assess the extent of joint damage, imaging tests are crucial.

MRI (Magnetic Resonance Imaging): Provides detailed images of soft tissues, allowing doctors to visualize the thickened synovium and pannus invasion.
CT (Computed Tomography) Scan: Offers high-resolution images of bone structures, useful for detecting erosions caused by pannus.
X-ray: While not as detailed as MRI for soft tissue, X-rays can show characteristic signs of joint destruction and bony erosions in advanced cases.

Comparison: Inflammatory vs. Degenerative Pannus


Feature	Inflammatory (Active) Pannus	Degenerative (Fibro-vascular) Pannus
Associated Condition	Early-stage Rheumatoid Arthritis, etc.	Chronic, untreated inflammation, contact lens wear, glaucoma, RA
Cellular Composition	High in inflammatory cells (leukocytes, lymphocytes)	High in fibrous, scar-like tissue (collagen)
Vascularity	Highly vascularized (hyper-vascularization)	Often less prominent vascular component
Progression	Rapid and aggressive tissue growth	Slow, progressive ingrowth over years
Reversibility	May show reversibility with aggressive treatment	Less reversible; often leaves behind hyalinized, acellular tissue
Clinical Sign	Spongy joint swelling	May appear fibrotic, hardened; limited joint function

Treatment and management strategies

The cornerstone of treating pannus is controlling the underlying condition, particularly in autoimmune diseases like RA. The goal is to halt the inflammatory process that drives pannus formation and joint destruction.

Medical interventions

Disease-Modifying Antirheumatic Drugs (DMARDs): These are the primary medications used to slow down the progression of RA and pannus formation. Examples include methotrexate, leflunomide, and sulfasalazine.
Biologics: For more severe or aggressive cases, targeted biologic agents can be used to block specific inflammatory pathways, effectively controlling inflammation and pannus growth. These include TNF inhibitors like adalimumab (Humira) and etanercept (Enbrel).
Corticosteroids: These can be used for rapid, short-term relief during acute flare-ups to reduce pain and inflammation.

Surgical interventions

When pannus has caused significant, irreversible damage, surgery may be necessary.

Synovectomy: Involves surgically removing the inflamed synovial tissue and pannus to relieve pain and improve joint function.
Joint Replacement or Fusion: If a joint is severely damaged, replacement surgery or fusion may be required to restore function or stability.

Conclusion: Managing degenerative pannus

Degenerative pannus represents a chronic manifestation of an underlying inflammatory process, often associated with autoimmune diseases like RA. While it may be less cellular and aggressive than active pannus, its fibrous nature can lead to irreversible joint destruction and pain over time. Early diagnosis and aggressive management of the root cause are paramount to prevent or slow its progression. Combining medications, physical therapy, and lifestyle adjustments provides the most effective pathway to preserve joint function and improve quality of life. For further information on managing chronic inflammatory conditions, consult resources like the Arthritis Foundation.

Disclaimer: The information provided in this article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for diagnosis and treatment of any medical condition.

Frequently Asked Questions

Inflammatory (active) pannus is highly cellular and aggressive, typically seen in the acute phase of inflammatory diseases. Degenerative pannus is a more chronic, fibrous, and less cellular tissue that results from long-term, untreated inflammation.

While early-stage, inflammatory pannus can be effectively managed and reduced with aggressive treatment, the fibrotic and scar-like nature of degenerative pannus makes it less reversible. Treatment can, however, prevent further damage.

No, pannus is not cancerous. While its growth can resemble that of a tumor, it is a benign, non-cancerous overgrowth of tissue that does not metastasize or spread to other parts of the body in the way cancer does.

Odontoid pannus is a type of pannus that forms around the odontoid process, a tooth-like projection in the neck's upper spine. It is commonly associated with rheumatoid arthritis but can also occur after trauma, causing potential spinal cord compression.

The main goal of treating pannus is to manage the underlying inflammatory disease, such as rheumatoid arthritis, to halt the abnormal tissue growth and prevent progressive, irreversible joint damage.

Yes, physical therapy can be an important part of managing the effects of pannus. It helps maintain joint flexibility, strengthen supporting muscles, and improve function, although it does not address the underlying inflammatory cause directly.

Treatment for corneal pannus varies depending on its cause. It may include managing underlying inflammation, treating chronic edema, and, in some cases, addressing severe contact lens wear issues. The fibrous scarring left by degenerative pannus may be permanent.