Intraepidermal Carcinoma.

IEC is seen every day in The Skin Cancer Clinic.

What is an an IEC (Intraepidermal Carcinoma) ?

IEC (Intraepidermal Carcinoma  is otherwise known as Bowen’s disease. There is a subtle difference between the two terms. Bowen’s is an IEC without a background of sundamaged skin. IEC tends to be the phrase used most often in Australia.

IEC is a type of squamous cell skin cancer but one that is confined only to the upper layer of skin (epidermis) – and is therefore fairly easys to treat. The abnormal squamous cells of an IEC are located throughout the epidermis. The IEC starts life as a Solar Keratosis – when the abnormal squamous cells involve only the lower part (base) of the epidermis.

With time, an IEC may develop into an Invasive Squamous Cell Carcinoma (SCC) – when these cancerous squamous cells haveespread down into the dermis.

So an IEC is intermediate between the ubiquitous Solar Keratosis, and an invasive Squamous Cell Carcinoma. An IEC is a “proper” skin cancer whereas the solar keratosis is, in effect, a “pre-cancer.”

All three of these lesions share the characteristic of sun damaged epithelial cells (keratinocytes) of the Epidermis (upper layer of the skin) caused by sun damage.

What is the risk of a Solar Keratosis turning into an IEC or Invasive SCC?

The risk is around 1-2% per year.

Where on the body is an IEC most likely to occur?

IEC is most commonly found on the face, neck or legs – all the heavily sun exposed areas. However, they can be found anywhere on sun-exposed areas.

The leg is a particularly common site in females. Males tend to develop an IEC on the head, neck &  below the forearms or lower legs – as a generalisation.

What does an IEC Look like?

A typical IEC (Bowen’s)  is a well defined, pink or red, scaly and flat (or almost flat) lesion. An IEC can look similar to a superficial BCC . However, an IEC typically has more scale and is more dull in colour than a superficial BCC – but these differences may be subtle or absent. The key tool to tell them apart is dermatoscopy.

IEC  may occasionally be pigmented and then look similar to a melanoma.