OBJECTIVETo emphasis the importance of recognizing and treating the early colorectal carcinoma with the invasion limited in the layer of muscularis mucosae, and discuss several questions in using the WHO's new diagnostic standards of the prestage of tumors of digestive system.

METHODSA retrospective review was made of 30 patients with invasive carcinoma limited in the layer of muscularis mucosae. All of the patients were treated between July 1986 and July 1999 in Shanghai Cancer Hospital.

RESULTSAmong the 30 cases, there were 19 men and 11 women from 20 to 80 years dd (mean, 57.0). The tumor diameter was ranged from 0.8 cm to 8.0 cm (mean, 2.9 cm). 12 patients were given polypectomy while 18 patients were given radical resection. Among the patients given polypectomy, one got recurrence 3 years later, one had the metastasis of lungs 50 months later and had been dead already. Among the patients given radical resection, one had metastasis of lymph nodes peripheral to the tumor, one also had the metastasis of lungs 68 months later but is still alive now, and one had metastasis of lymph nodes in the right upper part of neck 15 months later and then was lost to follow-up.

CONCLUSIONSThe patients with early colorectal carcinoma with the invasion limited in the layer of muscularis mucosae could have metastasis of lymph nodes, get local recurrence after polypectomy and even have blood metastasis. Therefore great attention must be paid. Clinicians should be careful to chosen polypectomy. Meanwhile, in order to provide more information of the correct treatment, it will be better if the pathologists could give the original diagnosis at the same time when they use the WHO's new diagnostic standards of the prestage of tumors of digestive system in diagnosing the early invasive carcinoma limited in the layer of muscularis mucosae, for the concept of high-grade intraepithelial neoplasia will be used instead of it, and whether or not it is a really benign tumor, much more clinical research must be done later.