How common is spindle cell squamous cell carcinoma?

Spindle cell squamous cell carcinoma (SCSCC) is an uncommon subtype of squamous cell carcinoma. It's estimated that there are 200,000 to 300,000 new cases of squamous cell carcinoma diagnosed in the United States each year. While the number of SCSCC cases diagnosed each year is unknown, the number is not very high. However, about one-third of the  squamous cell carcinoma cases that spread throughout the body are spindle cell.