Keratoacanthoma.

KA is a rapidly growing scaly nodule that mimics Squamous Cell Carcinoma.

What is a keratoacanthoma?

keratoacanthoma (“KA”) is a benign tumour of the sebaceous gland that starts as a red or skin-colored spot and and grows rapidly over weeks. They usually grow to between 1 and 3cm in size by which time it usually has a central crusted plug.

A Keratoacanthoma is a fairly common finding at a skin check although most people are aware they have a growth of some sort.

Keratoacanthoma certainly has many similarities with SCC (Squamous Cell Carcinoma). It is often very difficult to tell apart both clinically and pathologically. Keratoacanthoma may rarely itself develop into invasive SCC. Some experts believe that a KC is really a type of well differentiated (or “mild”) Squamous Cell Carcinoma.

KA can occur at any age but is slightly commoner between the age of 50 and 59.

Eventually, most Keratoacanthomas turn into scar tissue but this may take years. It is generally not considered safe to “wait and see.” The rationale for removing a Keratoacanthoma are:

  • There are rare reports of KA progressing to skin cancer.
  • Pathologists say that it may be very challenging to differentiate a KA from SCC.
  • It’s almost impossible to be clinically certain that a KA is not an SCC – the appearances are very similar even with a dermatoscope
  • KA may become large before they start to regress, and they do grow quickly. This period of growth will certainly cause alarm.

It’s almost impossible to be clinically certain that a KA is not an SCC – the appearances are very similar even with a dermatoscope.