Gastrointestinal Specimens: General Comments

Abstract

The type of histopathology resection specimen received is dictated by the nature of any previous operations and the current disease process, its distribution, and degree of local spread within the organ and to adjacent structures. Resection surgery must provide adequate clearance of longitudinal and deep circumferential radial margins. It must also take into account the lymphovascular supply to achieve satisfactory anastomoses and the regional lymph node drainage for an adequate radical cancer operation. Site location within any given organ may influence the nature of the pathological abnormality and surgical procedure undertaken, e.g., anterior resection for high rectal cancer versus abdominoperineal resection for low rectal cancer, or mid-esophagus (squamous carcinoma) versus distal esophagus (adenocarcinoma). Multifocal distribution may be seen in both inflammatory (Crohn’s disease) and neoplastic (malignant lymphoma) disorders. Inflammatory disease can be mucosa confined (ulcerative colitis), transmural (Crohn’s disease), or mixed (ischemic colitis). Tumor growth may be predominantly polypoid and intraluminal, with only a minor mural component and variable presentation depending on the organ involved, e.g., symptomatic dysphagia due to esophageal polypoid carcinoma or asymptomatic iron-deficiency anemia with a cecal carcinoma. Often cancer ulcerates and deeply invades the wall, stenosing and obstructing the proximal bowel with early access to mesenteric nodes, lymphovascular channels, and peritoneum, and potential perforation. Alternatively the tumor may be characterized by an intact mucosa and incipient thickening of the wall with a tendency for longitudinal spread and skip lesions (diffuse gastric carcinoma – linitis plastica). Thus, normal anatomy is variably distorted by differing disease processes, and this must be considered in handling the specimen to obtain appropriate management and prognostic data, e.g., depth of local tumor spread, peritoneal and regional lymph node involvement, and excision margin clearance. Allowance must also be made for variation in normal anatomy between and within individuals. For example, harvest of lymph nodes from the mesorectum is scanty compared to the sigmoid mesocolon, and in some patients few mesorectal nodes will be found. This is also made more difficult by preoperative radiotherapy, emphasizing the importance of taking into account the previous treatment history and request form information. The surgical histopathology specimen also acts as an audit tool for surgical practice and expertise, e.g., rates of anterior resection versus abdominoperineal resection or completeness of mesorectal excision in rectal cancers. Similarly it allows close correlation with preoperative clinical and radiological (e.g., MRI) assessment, and is a gauge of thoroughness of pathological examination. Thus, preoperative and operative techniques alter the specimen anatomy, resulting in differing management and prognostic implications for an equivalent degree of tumor spread in similar specimens from different patients.