F. Konishi et al., HISTOLOGICAL CLASSIFICATION OF THE NEOPLASTIC CHANGES ARISING IN ULCERATIVE-COLITIS - A NEW PROPOSAL IN JAPAN, Journal of gastroenterology, 30, 1995, pp. 20-24
Patients with total ulcerative colitis with a longstanding course of t
he disease have a high risk of developing colorectal carcinoma. Colono
scopic surveillance to detect precancerous tissue and/or cancer in the
se patients has been carried out in countries with a high incidence of
ulcerative colitis. Riddell's classification has been widely used for
the interpretation of biopsy specimens obtained from the colonoscopic
surveillance. In Japan, however, there are problems in accepting Ridd
ell's classification, mainly because the intramucosal carcinomas diagn
osed by Japanese histopathologists are included in the category of hig
h-grade dysplasia in Riddell's classification. Based on the results of
a meticulous slide review carried out by seven histopathologists in t
his study, a new classification is proposed: UC-I, inflammatory change
; UC-II, indefinite; UC-IIa, probably inflammatory; UC-IIb, probably n
eoplastic; UC-III, neoplastic but not carcinomatous; and UC-IV, carcin
oma. Intramucosal carcinoma is included in the category UC-IV. We cons
ider that the diagnosis of intramucosal carcinoma is to be made when t
here is a high grade of cytological and structural atypia consistent w
ith carcinoma. Interobserver and intraobserver variability with this c
lassification was acceptable. We believe this new classification will
be widely use in cancer surveillance in ulcerative colitis in Japan.