IEC is one of the most common skin cancers.
What are the clinical features?
A typical IEC is a well defined, scaly and flat (or almost flat) lesion that is pink, red, or brown in colour. The lesion can be up to several centimetres in diameter.
IEC is most commonly found on the face, neck or legs – all of the heavily sun exposed areas. However, they can be found anywhere!
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.
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. IEC may occasionally be pigmented in which case it can look similar to a melanoma.
The key tool to tell them apart is dermoscopy.
What else can look like an IEC?
Psoriasis .v. IEC
- Finding an IEC amongst a sea of psoriasis is not easy.
- Psoriasis may manifest for the first time with just one small lesion which can be easily confused with an IEC.
Gallery of IEC
IEC on The Face
Please click on the images for details.
What is the significance?
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.
What is the treatment?
Usual Treatment options are:
These are some of the key terms that may be used in the IEC Pathology Report
Full Thickness Keratinocyte Atypia
The Keratinocyte cells do not look typical. These “Atypical” Keratinocytes are found throughout the epidermis (“full thickness keratinocyte atypia”) – and not confined to the bottom layer(s) of the epidermis as found in a Solar Keratosis or IEC.
These atypical keratinocytes have the potential to invade down into the dermis. An untreated IEC may therefore develop into a squamous cell carcinoma (SCC).
Hyperkeratosis indicates extra keratin in the epidermis. This keratin accounts for the scale.
In the normal non-Parakeratotic skin, the keratinocytes lose their nuclei as they emigrate upwards within the epidermis to the stratum corneum. Keratinocytes are normally shed as dead cells without their nuclei.
Parakeratosis indicates that the keratinocytes have retained their nuclei after migrating from the bottom layer to the Stratum Corneum, and is a feature of IEC.
Acanthosis indicates a thickened layer within the epidermis – specifically the Stratum Basale & Stratum Spinosum where new keratinocytes are normally found.