Читать книгу Gastrointestinal Pathology - Группа авторов - Страница 33

In patients with chronic diarrhea and suspected microscopic colitis, random biopsies should be taken throughout the colon including at least two biopsies from the right, transverse, descending, and sigmoid colon. For limited sampling the flexible sigmoidoscopy is also a reasonable approach. In this case at least two biopsies should be obtained from the sigmoid and descending colon as well as transverse colon if this can be reached with the sigmoidoscope.

In the setting of inflammatory bowel disease, biopsy sampling should be performed to establish the diagnosis and to assess the extent. For the initial diagnosis, the American Society for gastrointestinal endoscopy recommends two biopsies from each of five sites including the ileum and rectum.

Surveillance of inflammatory bowel disease is a special circumstance and is evolving. Traditionally, random biopsies were obtained throughout the colon. Current guidelines recommend biopsy of each colonic segment with four‐quadrant biopsies every 10 cm from the cecum to the rectum for a minimum total of 33 biopsy samples. In cases where the entire colon is not affected, four samples should be obtained every 10 cm of the affected areas. More recently, it has been shown that using dye spray such as indigo carmine or methylene blue can identify areas of dysplasia with high accuracy and thus guide directed sampling without the need for random biopsy. Biopsies should however also be assessed from each colonic segment to assess for inflammation.