| [ Summary ] |
Endoscopic diagnosis of colorectal tumor is made on the basis of shape, size,color,fold convergence, bleeding, and so on. On the other hand, colorectal tumor suface structures (so-called pit pattern) were examined by stereomicroscope and magnifying electric endo-scope, and compared with histological findings. Kudo et al. carried out six types of pit pattern classification. Types I and II are non neoplasm, types IIIL and IIIS are tubular adenomas, type IV is mainly tubulovillous adenoma containing focal carcinoma and type V is mainly submucosal invasive cancer. Endoscopic differential diagnosis is difficult in the depressed type of colorectal tumor. Therefore, we have studied pit pattern and histological findings. Most have type IIIs and V pit patterns. We suggest that the lesions of type IIIS pit pattern are mostly tubular adenomas, but they contain tubular adenomas with severe atypia, intramucosal cancer and there are a few cases of submucosal invasive cancer. The lesions of type V pit patterns are mostly cancers, especially submucosal invasive cancer. However we must be careful of amorphism, non-structure and mucus interference under observation. It is concluded that pit pattern characterization is a helpful diagnostic clue in endoscopic examination in the depressed type of colorectal tumor. |