Squamous Cell Carcinoma.

A major type of skin cancer.

What is SCC (Squamous Cell Carcinoma)?

SCC is the second most common type of non-melanoma seen in the skin cancer clinic in Australia (after BCC). Squamous Cell carcinoma is a cancer of keratinocytes which are the cells found in the thin top layer of the skin called the epidermis.

This article refers to “Invasive SCC.” The other type of SCC is an Intraepithelial Carcinoma  (IEC). The appearance and treatment of invasive .v. IEC are different. The cancerous cells of an invasive SCC have spread into the dermis of the skin whereas the cancerous cells of an IEC remain in the epidermis (uppermost layer).

Invasive SCC usually occurs after the age of 40 and usually develops in a pre-existing Solar Keratosis. They usually occur in sun exposed areas, especially the head and neck. SCC is around 3 times more common in men than women.

Invasive SCC is unlike a BCC because an SCC may occasionally develop into a secondary cancer.

What does SCC look like?

SCC typically has at least one these features:

  • Fast Growing nodule
  • Ulceration
  • Feels Firm
  • Pain or Tenderness to touch
  • Raised, red and scaly (redness around the base can be a useful clue)

The appearance of an early SCC is similar to that of a thick (Hypertrophic) Solar keratosis. With further growth, an invasive SCC will typically be elevated and scaly. At this point, the base will be red and feel firm.  A keratoacanthoma may look very similar.

Sometimes, invasive SCC is not scaly and may look like a nodular melanoma.  Dermoscopy is very helpful although a biopsy will be required to make the final diagnosis & ensure the lesion has been removed. The type of solar keratosis that looks like an SCC is a “hypertrophic solar keratosis.”