What Is It?

Squamous cell carcinoma is the second most common form of skin cancer, accounting for around 20% of cutaneous malignancies. It is a tumour of epidermal keratinocytes, with the majority arising from actinic keratoses, while the reminder arise de novo. They can grow rapidly and can metastasize. They usually present on sun-exposed skin.

While most squamous cell carcinomas are nodules, some are ulcers. The majority can be excised by wide excision, although larger and more aggressive lesions may require Mohs micrographic surgery and/or radiotherapy.

As squamous cell carcinomas have metastatic potential, patients should be re-examined regularly, especially those presenting with high-risk factors.


Risk Factors for the Development of Squamous Cell Carcinoma

Risk Factors for the Development of Squamous Cell Carcinoma:

  • Fair skin, light eye colour, red or blonde hair

  • Age greater than 50

  • Skin types I and II

  • History of prior non-melanoma skin cancer

  • Exposure to tanning beds

  • Exposure to UV light

  • Genetic syndromes

  • Chronic immuno-suppression – there is a 65 – 250-fold increased risk of developing squamous cell carcinoma compared with the general population in patients on immuno-suppressive medications to prevent rejection in organ transplants.

  • Human Papilloma viruses are associated with squamous cell carcinomas

  • Chronic inflammation – chronic infections and non-infectious inflammatory disease have been associated with squamous cell carcinoma.

Actinic Keratosis, Bowen’s Disease and Squamous Cell Carcinoma

Actinic keratoses (Solar keratoses)

Pre-cancerous lesions of the skin which can lead to squamous cell carcinoma are actinic keratoses and Bowen’s disease. The rate of progression of an actinic keratosis to squamous cell carcinoma is small. Presentation will vary depending on the amount of scale from thin superficial lesions to thick, hyperkeratotic lesions.

Bowen’s Disease (Squamous Cell Carcinoma In-Situ)

Present as thin, pink patches or plaques. The rate of progression to squamous cell carcinoma can be as high as 3%.

Squamous Cell Carcinomas

Squamous cell carcinomas begin as skin-coloured, erythematous papules and plaques that develop into nodules. The lesions are often tender and can be associated with a significant degree of thickness. The most frequent physical sign of squamous cell carcinoma is induration (thickening at the edge or base of the lesion, which represents dermal infiltration). Ulceration usually occurs if the lesion has increased in size.

Surgical Management

Surgical Excision – is the treatment of choice for squamous cell carcinoma. Depending upon the tumour, as long as there are no associated high-risk features, providing suitable margins will prove most effective.

Mohs Micrographic Surgery – has the highest cure rate of all surgical treatments because the tumour is microscopically delineated until it is completely removed. It is indicated for treatment of the following:

  • Primary squamous cell carcinomas occurring at sites known to have a high initial treatment failure following traditional methods.

  • Primary tumours with poorly defined clinical borders.

  • Primary tumours with diameters of more than 2cm.

  • Primary tumours arising in regions where maximal preservation of uninvolved tissue is desirable.

  • Recurrent squamous cell carcinomas.

  • Squamous cell carcinomas that show perineural invasion.

Curettage and Electro-Dessication – can be considered to treat low-risk squamous cell carcinomas involving the trunk and extremities. Treatment side-effects include thickened scars, incomplete removal and lack of histological control.


  • Squamous cell carcinomas can grow rapidly and have the capacity to metastasize.

  • Usually present on sun-exposed skin.

  • Most squamous cell carcinomas are nodules; some are ulcers.

  • Mohs micrographic surgery has the highest cure rate for both primary and recurrent tumours. As squamous cell carcinomas have metastatic potential, patients should be re-examined regularly, especially those presenting with high-risk factors.

What’s the next step?

If you already have an appointment booked at The Skin Specialist Centre, you can easily add a squamous cell carcinoma treatment consultation to your booking by calling our friendly team on (09) 524 5011. If you have never been to The Skin Specialist Centre, you can either give us a call on (09) 524 5011 or make an enquiry by clicking on the Enquire Now option below.