Robert Lev

Endoscopically removed malignant colorectal polyps: Clinicopathologic correlations

BACKGROUND/AIMS Treatment options for patients with endoscopically removed malignant colorectal polyps are polypectomy alone vs. polypectomy followed by surgery. The aim of this study was to define histopathologic parameters that can be used for clinically relevant treatment decisions. METHODS Five pathologists evaluated 140 polyps for the presence or absence of unfavorable histology. Unfavorable histology was tumor at or near (< or = 1.0 mm) the margin and/or grade III and/or lymphatic and/or venous invasion. Adverse outcome was recurrent and/or local cancer and/or lymph node metastasis. RESULTS Adverse outcome was 19.7% (14 of 71), 8.6% (2 of 23), and 0% (0 of 46) when unfavorable histology was present, indefinite (lack of agreement), and absent, respectively (P < 0.0005, present vs. absent). Four patients with cancer > 1.0 mm from the margin had an adverse outcome (2 with lymphatic invasion and 2 indefinite for lymphatic invasion). Four patients with negative resections later developed distant metastases. Eight patients (6.3%) died of disease, and 2 of 69 without unfavorable histology (both indefinite for lymphatic invasion) had an adverse outcome. Interobserver strength of agreement was substantial to almost perfect for margin, grade, and venous invasion and fair to substantial for lymphatic invasion. CONCLUSIONS This system is usable clinically. Patients with unfavorable histology are probably best managed by resection postpolypectomy, whereas in the absence of unfavorable histology, they probably can be treated by polypectomy only.

Histologic and morphometric study of chronic gastritis in alcoholic patients.

The effect of chronic alcohol ingestion on the gastric mucosa was determined in 96 patients in whom gastroscopy was performed because of upper gastrointestinal symptoms. Seventy-two patients were classified as alcoholics and 24 patients as nonalcoholics. In all cases biopsy specimens were taken from the fundus and antrum. The diagnoses of chronic superficial and atrophic gastritis were based on conventional histologic criteria and a morphometric technique utilizing quantitation of the chronic inflammatory cells in the lamina propria. Alcoholic patients were found to have a higher incidence of chronic gastritis of the antrum than nonalcoholics (p less than 0.001). Fundic involvement was also more common, probably accounting for the decreased gastric acid output described in chronic alcoholic patients. Finally, gastritis was more severe in the alcoholics; below 45 years of age chronic atrophic gastritis was seen only in alcoholics. We conclude that chronic gastritis develops more frequently in alcoholic patients and evolves into chronic atrophic gastritis at an earlier age than in nonalcoholic subjects.

Precursors of human colon carcinoma: a serial section study of colectomy specimens.

All polyps and strips of colonic mucosa 1 to 15 cm from tumor margins were examined for possible precursors of carcinoma in 24 patients undergoing partial colectomy for primary colorectal adenocarcinoma. Of 114 polyps found, 40.4% were adenomatous, and the remainder were hyperplastic or inflammatory or showed normal mucosa. No primarily dysplastic lesions, which could be interpreted as early de novocarcinomas, were found. Serial sections of mucosal strips revealed minute adenomatous foci in 3 of 24 patients, one of whom also showed several patches of exclusively dysplastic epithelium. This finding suggests that carcinomas may rarely arise de novo, but most carcinomas appear to be accompanied by (? preceded by) adenomatous changes.

Colonic oligosaccharide structures deduced from lectin-binding studies before and after desialylation

Dolichos biflorus agglutinin (DBA) binds N-acetylgalactosamine (GalNAc), and peanut agglutinin (PNA) binds Gal beta(1-3)GalNAc residues (Gal = galactose). We used these lectins with neuraminidase to probe colonic oligosaccharides. Tissues included normal epithelium, adenocarcinomas (T) with contiguous transitional (TM) and normal mucosae (RM), and adenomatous polyps. Except for DBA binding in carcinomas, neuraminidase digestion increased DBA and PNA binding in all epithelia. In untreated specimens, reciprocal gradients for binding by DBA (T less than TM and TM less than RM) and PNA (T greater than TM and T greater than RM) were seen. After neuraminidase, all gradients were abolished except for T less than TM and T less than RM with DBA. We conclude that (1) qualitative as well as quantitative differences may exist between the mucins of benign and neoplastic colonic epithelium, (2) the NeuAc-GalNAc dimer is a widely prevalent terminal oligosaccharide in benign epithelium at all stages of differentiation (NeuAc = sialic acid), and (3) in contrast with evidence from recent biochemical studies, the Gal beta(1-3)GalNAc dimer is a common masked oligosaccharide in benign epithelium.

Detection and Management

In this section, there will be a discussion of the general principles of screening and their application to colorectal neoplasia. This will be followed by a description of the various methods of examining the colon, including for each technique the extent of accessible bowel, the sensitivity and specificity for detection of neoplastic lesions, and the complication rates of the procedures.

Histochemical and morphological analysis of colonic epithelium from children with Gardner's syndrome and adults bearing adenomatous polyps.

Normal and adenomatous colonic tissues from children with Gardners syndrome were compared to analogous tissues from adults bearing adenomatous polyps using mucin histochemical and lectin-binding techniques. Adenomatous tissue from children exhibited general morphological similarity to its adult homologue, but showed less dysplasia. Its goblet cells stained weaker for mucins and the lectins Dolichos biflorus agglutinin (DBA) and peanut agglutinin (PNA). This suggested un-derglycosylation of side chains of mucins in these childhood adenomas. The weak DBA and relatively intense sulfomucin staining in these adenomas suggested that they arose from deep crypt cells. Adult adenomas shared certain histochemical properties with carcinomas, namely, increased affinity for periodic acid-Schiff (PAS) and focally for PNA. There is evidence based on the effects of saponification and sialidase treatments that the weak initial PAS reaction in normal and adenomatous colonic goblet cells from both age groups results from sub-stituents on sialic acid and, in the case of normal colon from children, on other monosaccharides as well. Finally, there was a frequent lack of parellelism between PAS and lectin staining suggesting that different groups within the sugars are responsible for reactivity with those compounds.

On the difference between colonic and small intestinal alkaline phosphatase.

Colonic and small intestinal alkaline phosphatase extracts were studied biochemically and electrophoretically to elucidate the source of a reported difference in cellulose acetate electrophoretic mobility. Both preparations were inactivated with 0.5 mmol/L L-phenylalanine but retained full activity in the presence of 1.0 mmol/L tetramisole. Treatment with neuraminidase changed a minor fraction of the small intestinal but the major portion of the colonic alkaline phosphatase to a cathodically migrating form. The most likely explanation for our findings is that the colon and small intestinal alkaline phosphatase are mixtures of the same multiple forms but in different proportions.

Malignant Potential of Adenomatous Polyps

Adenomatous polyps (APs) that contain invasive carcinoma will be discussed in Chap. 5.B, and the parallel occurrence of polyps and colorectal carcinomas (CRCs) in various population groups will be explored in Chap. 4.D. The coexistence of polyps and separate synchronous or metachronous (subsequent) carcinoma in the same individual will be discussed here. Although the epidemiological studies described in Chap. 4.D suggest a relationship between adenomatous polyps and carcinoma, they do not directly address the questions of (1) whether persons with adenomatous polyps are at elevated risk of subsequent CRC and, if so, (2) the size of the risk and its relation to pathological features of the polyp.