Book 4 - Self Instructional Manual for Cancer Registrars - SEER ...

Malignantand Benign TumorsThe usual histologic type of intestinal malignancy is adenocarcinoma. Squamous cell carcinomaarises in the anus; cloacogenic transitional cell carcinoma arises at the anorectal junction. Tumorsarising on the right side of the colon tend to be cauliflower-type lesions; those on the left encirclingor "napkin-ring" type.Carcinoids are the most common appendicial tumors. They rarely metastasize. There is adifference of opinion among pathologists as to the criteria for determining their malignancy.There are some premalignant conditions of which you should be aware. Adenomatous polyps aresmall reddish lesions, frequently on a stalk, which are important because of the possibility of theirbecoming malignant. Villous adenomas are soft, spongy, sessile lesions which arise from the bowelwall and have an even higher likelihood of becoming malignant. Familial polyposis, a hereditarypolypoid disease, has a marked tendency to undergo malignant change. Ulcerative colitis may alsobe a precursor of malignancy. You may be required to include some of these diagnoses in yourregistry, or, at least, record these conditions if they are mentioned in the history of a patient withmalignant disease of the colon.Figure 37. LYMPHATIC DRAINAGE OF THE COLON AND RECTUM222