Squamous cell carcinoma in situ is an early form of squamous cell carcinoma that is confined to the outer layer of the skin (epidermis) and has not yet invaded the deeper layers.
Squamous cell carcinoma in situ (formerly called Bowen disease) most commonly occurs on sun-exposed areas of the skin but may occur anywhere.
There may be many carcinomas or only a few. The affected skin is red-brown and scaly or crusted and flat, sometimes looking like a patch of psoriasis, dermatitis, or a fungal infection called tinea or ringworm.
DR P. MARAZZI/SCIENCE PHOTO LIBRARY
Diagnosis of Squamous Cell Carcinoma in Situ
Biopsy
A biopsy is the standard procedure for confirming the diagnosis of squamous cell carcinoma in situ. During this procedure, doctors remove a piece of the tumor and examine it under a microscope.
Treatment of Squamous Cell Carcinoma in Situ
Removal of the cancer
Doctors may remove the cancer in the office by scraping and burning it with an electric needle (a procedure called curettage and electrodesiccation) or by cutting it out. Doctors may destroy the cancer by applying extreme cold (cryosurgery), an electrical current (electrocautery), or chemotherapy to the skin.
Prevention of Squamous Cell Carcinoma in Situ
Because squamous cell carcinomas seem to be related to UV light exposure, doctors recommend a number of measures to limit UV light exposure, starting in early childhood:
Avoiding the sun: For example, seeking shade, minimizing outdoor activities between 10 AM and 4 PM (when the sun’s rays are strongest), and avoiding sunbathing and the use of tanning beds
Wearing protective clothing: For example, long-sleeved shirts, pants, and broad-brimmed hats
Using sunscreen: At least sun protection factor (SPF) 30 with UVA and UVB protection used as directed and reapplied every 2 hours and after swimming or sweating but not used to prolong sun exposure
More Information
The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
American Cancer Society: What Are Basal and Squamous Cell Skin Cancers?: Information about skin cancers, including detection, prevention, treatment options, and other resources
The Skin Cancer Foundation: Squamous cell carcinoma: Information about squamous cell carcinoma, including detection, prevention, treatment options, and other resources
