Rectal tumors should clinically be rectal adenomas. Rectal adenoma is distinguished from rectal cancer by histopathologic examination of the biopsy. Histopathology, or biopsy for short, can be used to identify benign and malignant tumors. Generally, the lesion and its adjacent normal tissues are excised and sent for examination. 1. Pathological manifestations of rectal adenoma: tubular adenoma: single or multiple growths, usually not more than 2cm, well differentiated; villous adenoma: single nodule, usually without clitoris, easy to bleed; villous tubular adenoma: both of the above two manifestations. 2. Pathological manifestations of rectal cancer: early stage: confined to mucous membrane layer and submucous membrane layer, divided into bulging type and flat bulging type. Middle and late stage: tissue infiltration exceeds the submucosal layer, deepens to the muscular layer and plasma membrane layer, and is divided into bulging type and ulcerated type. Rectal adenoma may develop into rectal cancer. If rectal adenoma is found, please consult doctor for timely and standardized treatment. If rectal adenoma is diagnosed as rectal cancer, please follow the doctor’s instruction for treatment.