Flat and depressed colorectal tumours in a southern Swedish population: a prospective chromoendoscopic and histopathological study
- 1Endoscopy Unit, Department of Radiology, University Hospital Malmö, Sweden, and Department of Gastroenterology, Chikushi Hospital, Fukuoka University, Japan
- 2Department of Pathology, University Hospital Malmö, Sweden
- 3Endoscopy Unit, Department of Radiology, University Hospital Malmö, Sweden
- Correspondence to:
Dr B Veress, Department of Pathology, University Hospital MAS, 205 02 Malmö, Sweden;
- Accepted 15 January 2002
Background: Flat and depressed colorectal tumours are common in Japan but are very rare or non-existent in Western countries.
Aims: To study the occurrence of flat colorectal tumours in a southern Swedish population.
Methods: In this prospective study, 371 consecutive European patients were examined by high resolution video colonoscopy combined with chromoendoscopy. The nature of the lesions was determined by histopathological examination.
Results: A total of 973 tumours were found; 907 (93.2%) were protruding and 66 (6.8%) were flat or depressed. Of the flat/depressed tumours, five (7.7%) were early adenocarcinomas infiltrating the submucosa. Eleven carcinomas (1.2%) were found among protruding tumours. High grade dysplasia was observed in 18% (n=11) of flat/depressed adenomas in contrast with 7.3% (n=65) of protruding adenomas, and occurred in smaller flat/depressed tumours compared with protruding ones (mean diameter 8 mm v 23 mm, respectively). Furthermore, high grade dysplasia was significantly more common in flat elevated tumours with central depression or in depressed adenomas (35.7%; 5/14) than in flat elevated adenomas (12.8%; 6/47).
Conclusion: Flat and depressed tumours exist in a Western population. Future studies should address whether or not chromoendoscopy with video colonoscopy is necessary in the search for flat colorectal neoplasms.