Squamous cell carcinoma in situ


Squamous cell carcinoma in situ


Bowen's disease is a very early form of skin cancer, which is easily curable. The main sign is a red, scaly patch on the skin.

The abnormal growth takes place in the squamous cells – the outermost layer of skin – and Bowen's disease is sometimes referred to as "squamous cell carcinoma in situ".

Sometimes, the cancerous cells spread along the skin's surface, but it is usually very slow-growing and may not change for years.

Only occasionally (in 3-5% of patients) does Bowen's disease invade the deeper layers of skin and turn into a more serious type of skin cancer. However, this is only a risk if it's left undiagnosed or neglected.

It's important to get a proper diagnosis, as Bowen's disease can look like other conditions, such as psoriasis or eczema.

Always see your GP if you have a red, scaly patch of skin and don't know the cause. If necessary, your GP will refer you to a dermatologist to determine the cause of your skin condition.


Which parts of the skin does it affect?

Bowen's disease can appear anywhere on the skin, especially the trunk, arms or legs.

It is most commonly found on the lower leg of elderly women (see "who is affected" section, below).

Occasionally, it can affect the genital area or, in men, the penis. This type of Bowen's disease is known as bowenoid papulosis or Bowen's disease of the penis.


What are the symptoms?

Bowen's disease usually appears as a persistent reddened scaly patch on the skin that is 1-3cm in diameter and which may or may not be itchy.

The affected skin can be red and sore, and may bleed and scab.

Bowenoid papulosis appears as a brown patch around the groin area.


Who is affected?

Bowen's disease is more common in women than men, and usually affects older people in their 70s-80s.

It tends to be seen on people who have had lots of sun exposure (one of the main causes), especially those with fair skin.

It's also more likely to affect people who take medication to suppress their immune system (for example, those who have just had an organ transplant).


What are the causes?

The causes of Bowen's disease are often unknown. It doesn't run in families and you can't pass it on to others.

Most cases develop as a result of long-term exposure to the sun, and people with fair skin are more at risk of developing it.

However, this is not the only cause, as Bowen's disease can develop in areas of the skin not normally exposed to the sun.

Having radiotherapy also puts you at increased risk of developing Bowen's disease in the affected area.

Rarely, it is related to arsenic exposure.

Bowenoid papulosis (affecting the genital area) may be caused by the same human papillomavirus (HPV) that causes genital warts.


How is it treated?

There are a number of treatment options and your dermatologist will take into consideration where the patch is on your body, as well as the size, thickness and number of patches you have before deciding on the most appropriate procedure. 

They will also consider how well your skin is likely to heal afterwards – for example, skin on the lower legs tends to be tight, fragile and slow to heal.

Treatment options include:

Cryotherapy – Liquid nitrogen is sprayed onto the affected skin to freeze it. The procedure may be painful and the skin may remain a bit uncomfortable for a few days. The treated area may blister and weep. The patch will scab over afterwards and usually fall off within a few weeks, removing the affected skin.

Imiquimod cream or chemotherapy cream, such as 5-fluorouracil – This is applied to the affected skin regularly over a period of time. It may cause your skin to become red and inflamed before it gets better. 

Curettage and cautery – The affected area of skin is scraped away under local anaesthetic, and heat or electricity is used to stop any bleeding, leaving the area to scab over and heal after a few weeks.

Photodynamic therapy – A light-sensitive cream is applied to the affected skin, and a laser is directed onto the skin four to six hours later, to destroy the abnormal cells. The treatment session lasts about 20-45 minutes. A dressing covers the area afterwards, to protect it from light. You may need more than one session.

Surgery – The abnormal skin is cut out and stitches may be needed afterwards. It is not the best option if the patch is large or if there are several patches.

Talk to your dermatologist about which treatment is most suitable for you.

In a minority of cases, your dermatologist may just advise monitoring the Bowen's disease closely, as it's very slow-growing and (because of the treatment's side effects) may not be worth treating.


Caring for your skin afterwards

After treatment, you may need follow-up appointments with your dermatologist or GP to see if you need any further treatment.

If you had surgery to remove the patch, followed by stitches, you will need to have the stitches removed by your GP one to two weeks later.

In the meantime, if your patch starts to bleed, change in appearance or a new lump develops, see your GP or nurse for advice immediately – don't wait for your follow-up appointment.

Always make sure you protect your affected skin from the sun – wear protective clothing and use a sunscreen with a high sun protection factor (SPF) of at least 30. 



Bowen's disease often grows very slowly, over a period of months or years. All the above treatments work well for Bowen's disease, and the cure rates are high.

If Bowen's disease is not diagnosed and monitored, it can eventually turn into squamous cell cancer in a small number of people (about 3-5 in every 100 affected people). 



Protect your skin and eyes

How to keep safe from sun damage (including sunbeds) and reduce the risk of skin cancer