Primary rectal squamous cell carcinoma resembling a submucosal tumor.

Primary rectal squamous cell carcinoma is an extremely rare tumor and, in most cases, detected at an advanced stage. In our case, the tumor was at an early stage and had a submucosal appearance. Thus, the tumor was difficult to differentiate from other rectal submucosal tumors and, it was removed by endoscopic submucosal dissection for excisional biopsy.