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Ronna F. Lodato, M.D.patients, rectal site). Tiny nodes may measure only 1-2 millimeters,and these pinpoint structures are challenging for the pathologist to seeand feel in what may be an abundance of fat attached to the colorectalspecimen. It’s important to find all of the lymph nodes and examinethem microscopically for the presence of absence of metastatic cancer.The goal for the surgeon and pathologist for accurate staging is toretrieve at least 12 lymph nodes from all colorectal surgical resections.Once the areas of interest of the colorectal polyp or tumor areselected during gross examination and dissection by the pathologist,the tissue is processed overnight by progressive dehydration, and thenembedded in paraffin wax by histotechnologists in our laboratory.These formalin-fixed, paraffin-embedded tissues are then cut inapproximately 4-5 micron slices and mounted on slides which arethen stained, and examined by the pathologist using a microscope.Polyps are of many types, the two most common of whichare completely benign hyperplastic polyps, and precancerousadenomatous polyps. All are examined carefully to exclude thepresence of carcinoma. Biopsies of carcinomas are also performedendoscopically, and are likewise carefully examined to confirm theendoscopist’s impression of cancer and provide details about themicroscopic appearance in the pathology report.Microscopic examination of the resected colorectal cancerspecimen is a detailed process, and includes creating a report whichclarifies the characteristics of the cancer. These include:• type of cancer (the vast majority of colorectal cancers areadenocarcinomas)• grade or degree of differentiation (how closely the tumorresembles normal colorectal glands)• depth of invasion by the cancer into the colorectal wall (the “T”stage)• presence or absence of lymphatic or vascular invasion• presence or absence of lymph node metastases, their number andsize (the “N” stage)• status of the margins (whether the cancer was completelyremoved)• any other polyps or abnormalities in the specimenIn addition, in patients who have undergone pre-operativechemotherapy and /or radiation therapy, the pathologist assessesfor treatment effect, which provides information on how well thetumor has responded to the treatment. If there is clinical evidenceof metastatic carcinoma beyond the colorectal lymph nodes, thosesites (the most common is the liver) are typically biopsied and thepathologist examines the tumor to ensure it is similar in microscopicappearance to the colorectal cancer. All of this detailed information isincluded in a comprehensive pathology report and to provide detailsfor the treating physicians (surgeon, oncologist, radiation oncologist)12