Usefulness of magnifying endoscopy for diagnosing tumorous lesions of the colorectum.

The usefulness of magnifying endoscopy was assessed by examining the extent to which a magnifying endoscope can provide images of pits and by analyzing the consistency of the pit patterns visualized by magnifying endoscopy with the pit patterns visible under a stereomicroscope. Study materials consisted of 83 cases of tumorous colorectal lesions. Under a magnifying endoscope, pits were visible across the entire surface of the lesion in 46 (55.4%) of the 83 cases. The pit pattern visualized by magnifying endoscope in 32 (69.6%) of the 46 cases was identical to the pattern observed under a stereomicroscope. Of various pit patterns, type IIIs (tubular, round pit that is smaller than normal pit), type IIIL (tubular, round pit that is larger than normal pit) and type IV (dendritic, gyrus-like type pit) were relatively well visualized under a magnifying endoscope. It was difficult to obtain images of type V (irregular or amorphous pit) with a magnifying endoscope. It seems therefore easy to distinguish tumors from non-tumorous lesions using a magnifying endoscope. This imaging technique may provide information more useful for the diagnosing tumorous colorectal lesions and selecting therapeutic strategy, if staining methods and mucus-removing methods are improved.