Chronic skin injuries such as long-standing scars, old burn sites, and persistent ulcers carry a small but significant clinical risk of developing into squamous cell carcinoma. While most scars remain stable for a lifetime, those subjected to repeated irritation, chronic inflammation, or poor healing can undergo malignant changes over many decades. In the United Kingdom, these specific types of skin cancer are sometimes referred to as Marjolin ulcers, and they are recognised by dermatologists as requiring careful monitoring because they can behave more aggressively than standard sun-related skin cancers. Understanding the warning signs of this transformation is essential for anyone managing a permanent skin change resulting from a previous injury or medical condition.
What We’ll Discuss in This Article
- The clinical definition and causes of a Marjolin ulcer
- Identifying warning signs in old burn scars and chronic wounds
- Why chronic inflammation leads to malignant cell changes
- The typical timeline for cancer to develop in a scarred area
- Management and diagnostic steps for suspicious chronic scars
- Why early intervention is vital for scars on the limbs and trunk
Understanding the development of the Marjolin ulcer
A Marjolin ulcer is a specific type of squamous cell carcinoma that arises within a pre-existing area of damaged or scarred skin. This process is distinct from standard skin cancer because it is driven by chronic irritation and poor blood supply rather than direct ultraviolet radiation. The National Health Service states that squamous cell carcinoma can occasionally develop in areas of skin that have been damaged by previous burns, long-standing sores, or chronic inflammation. These tumours are often found in scars resulting from severe burns, radiotherapy, or chronic leg ulcers that have failed to heal over several years.
The biological reason for this change is linked to the constant cycle of tissue damage and attempted repair within a restricted environment. Because scar tissue often has a limited blood supply and reduced immune surveillance, the body is less effective at identifying and removing cells that develop genetic errors during the repair process. Over time, these errors can accumulate until a group of cells begins to grow uncontrollably, forming a malignancy within the boundary of the original scar. While these cases represent a small percentage of all skin cancers in the UK, they are clinically important because they often occur in areas not typically exposed to the sun.
Identifying warning signs in old scars and burns
Recognising the transformation of a stable scar into a malignancy requires a high degree of clinical suspicion, as the changes can be subtle at first. One of the most common early signs is the development of a new, persistent sore or ulcer within the scar that does not heal with standard wound care. You might also notice that the scar starts to thicken, or a firm, raised lump begins to grow from a previously flat area. These changes often occur twenty to thirty years after the original injury, making them easy to overlook in the context of a lifelong mark.
NICE clinical guidelines recommend an urgent referral for any patient with a chronic skin ulcer or a change in a long-standing scar that shows signs of rapid growth, bleeding, or induration. Other symptoms to monitor include a foul-smelling discharge from the wound, increased pain or tenderness in a previously painless scar, and the development of a cauliflower-like growth on the surface. Because these cancers grow within a restricted area of fibrous tissue, they may eventually invade deeper structures like muscle or bone if they are not identified and treated by a specialist surgical team.
The significance of chronic inflammation
Chronic inflammation is the primary driver of malignant transformation in old scars and wounds. When a part of the skin is constantly inflamed, such as in a long-standing venous leg ulcer or a deep burn scar that frequently cracks and bleeds, the cells are under continuous stress. This persistent irritation forces the skin cells to divide more frequently to repair the damage, which increases the statistical probability of a genetic mutation occurring. Unlike a healthy part of the skin, the scar environment lacks the normal regulatory signals that keep cell growth in check.
In the United Kingdom, patients with conditions like hidradenitis suppurativa or chronic osteomyelitis (a bone infection that drains through the skin) are monitored for these changes. The presence of long-term infection and inflammation creates a pro-cancerous environment where cells can slowly transition from benign to malignant. This is why UK healthcare providers emphasise the importance of professional wound management for any chronic sore. Ensuring that a wound is kept clean and supported to heal effectively is the best way to reduce the underlying inflammation that could otherwise lead to a squamous cell carcinoma in the future.
Diagnostic and management steps in the UK
If a clinician suspects that a scar or chronic wound is undergoing malignant change, the first step is usually a diagnostic skin biopsy. This involve taking a small sample of the suspicious tissue to be examined under a microscope by a pathologist. Because Marjolin ulcers can be quite large, the doctor may take several samples from different parts of the wound to ensure an accurate diagnosis. If a squamous cell carcinoma is confirmed, the primary treatment is usually a wide surgical excision to remove the cancer and a significant margin of the surrounding scar tissue.
In some cases, especially if the cancer is located on a limb or near a joint, the surgical team may involve plastic surgeons to perform a skin graft or a flap to repair the defect. This is necessary because the surrounding skin is often already scarred and less flexible than healthy tissue. Following surgery, some patients may also be offered radiotherapy to ensure any remaining microscopic cells are destroyed. Because these specific cancers have a slightly higher risk of spreading to local lymph nodes compared to sun-related SCC, the follow-up process in the NHS is often quite rigorous to ensure long-term patient safety.
Conclusion
Long-standing scars and burn areas can occasionally turn into a type of squamous cell carcinoma known as a Marjolin ulcer. This transformation is driven by chronic inflammation and usually occurs several decades after the original skin injury. Identifying new ulcers, lumps, or persistent bleeding within an old scar is essential for securing a prompt diagnosis and achieving a successful clinical outcome.
If you experience severe, sudden, or worsening symptoms, call 999 immediately.
How long does it take for a scar to become cancerous?
The process is very slow and typically takes between twenty and thirty years from the time of the original injury, though rare cases have occurred sooner.
Are all old scars at risk of turning into SCC?
No, the vast majority of scars remain benign; the risk is primarily associated with scars that are frequently irritated, inflamed, or fail to heal properly.
Does a Marjolin ulcer hurt?
A new pain or a change in sensation within an old, stable scar is a significant warning sign and should be reviewed by a healthcare professional.
Can a scar on my face turn into an SCC?
Yes, but most cancers on the face are caused by direct sun exposure rather than the scarring process itself.
Why is it called a Marjolin ulcer?
It is named after Jean-Nicolas Marjolin, a French surgeon who first described these specific changes in burn scars in the nineteenth century.
Is surgery the only treatment for this type of SCC?
Surgery is the primary cure, but radiotherapy may also be used depending on the size and location of the tumour and the health of the surrounding skin.
Can a leg ulcer turn into cancer?
Yes, any chronic ulcer that has been present for many years and shows new growth or fails to respond to standard treatment should be biopsied.
Authority Snapshot (E-E-A-T)
This article is designed to provide clear and factual information regarding skin health for the general public. The content is written by the Medical Content Team and has been reviewed by Dr. Stefan Petrov. He is a UK-trained physician with an MBBS and postgraduate certifications including Basic Life Support (BLS), Advanced Cardiac Life Support (ACLS), and the UK Medical Licensing Assessment (PLAB 1 & 2). He has hands-on experience in general medicine, surgery, anaesthesia, ophthalmology, and emergency care. Dr. Petrov has worked in both hospital wards and intensive care units, performing diagnostic and therapeutic procedures, and has contributed to medical education by creating patient-focused health content and teaching clinical skills to junior doctors.
