Differences in diagnostic criteria for esophageal squamous cell carcinoma between Japanese and Western pathologists

BACKGROUND. Large discrepancies have been found between Western and Japanes e pathologists in the diagnosis of adenoma/dysplasia versus carcinoma for g astric and colorectal glandular lesions. It is important to determine wheth er similar differences exist in the diagnosis of esophageal squamous lesion s. METHODS. Eleven expert gastrointestinal patholagists from Japan, North Amer ica, and Europe individually reviewed a set of microscopic slides containin g 21 sections of biopsies and corresponding endoscopic mucosal resection sp ecimens from Japanese patients with superficial esophageal squamous neoplas tic lesions. The pathologists indicated the pathologic findings on which th ey based each diagnosis. RESULTS. Invasion was the most important diagnostic criterion of carcinoma for the Western pathologists whereas nuclear and structural features were m ore important far the Japanese pathologists. For two sections showing low g rade dysplasia according to most Western pathologists, the Japanese patholo gists diagnosed suspected carcinoma in one case and definite carcinoma in t he other. For nine sections with high grade dysplasia according to the West ern pathologists, the Japanese pathologists diagnosed suspected carcinoma i n two cases and definite carcinoma in seven cases. For six sections with su spected carcinoma according to most Western pathalogists, the Japanese path ologists diagnosed suspected carcinoma in one case and definite carcinoma i n five cases. Four sections showed definite carcinoma according to both the Western and Japanese pathologists. Thus, there was agreement among the Wes tern and Japanese pathologists for only 5 of the 21 sections (kappa value, 0.04). However, when high grade dysplasia, noninvasive carcinoma, and suspe cted carcinoma were grouped together, the agreement was excellent (19 of th e 21 sections; kappa value, 0.75). CONCLUSIONS. In Japan, esophageal squamous cell carcinoma is diagnosed main ly based on nuclear criteria, even in cases judged to be noninvasive low gr ade dysplasia in the West. This difference in diagnostic practice may contr ibute to the relatively high incidence rate and good prognosis of superfici al esophageal carcinoma in Japan. To improve the comparability of research data, the authors recommend that high grade dysplasia, noninvasive carcinom a, and suspected carcinoma be grouped together into one category of "noninv asive high grade neoplasia." (C) 2000 American Cancer Society.