IEC is one of the most common skin cancers.
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 easy 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 have spread 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 relatively low – around 1-2% per year.