胃生検“indefinite for neoplasia，Group 2”診断症例の臨床病理学的検討

Clinicopathological Study of Cases Indefinite for Neoplasia, Group 2, for Gastric Biopsy

要旨　改訂された胃生検Group分類におけるGroup 2（indefinite for neoplasia）病変について，臨床病理学的に検討した．Group 2と診断した症例は83例（0.6％）であった．病変切除または十分な経過観察が行われたのは66例（79％）で，最終結果は癌が23例（28％），再生異型（非腫瘍）が40例（48％）であった．癌はすべて分化型癌のpT1a（M）で，大部分が低異型度癌であった．生検組織診時点で推定した疾患とは21％で異なっていた．Group 2となった原因は，癌症例では検体量が不十分なものが多く，再生異型症例ではびらん炎症により修飾されたものが多かった．病変の質的分類を採用した新Group 2分類は再生検を要する症例を的確に伝達できるが，その活用には病理医や臨床医へのさらなる浸透が必要と考えられた．

　Cases with the diagnosis of group 2（indefinite for neoplasia）in a revised group classification for gastric biopsy specimens were clinicopathologically studied. 83 cases（0.6％）were diagnosed as Group 2. The lesions of 66 cases（79％）were resected or were put under close observation. The final diagnoses of the lesions were carcinomas, 23 cases（28％）, and nonneoplastic lesions with regenerative atypia, 40 cases（48％）. Histologically, all cases of carcinoma were differentiated type and pT1a（M）, and almost all cases showed low-grade atypia. The final diagnoses of 21％ of cases with Group 2 didn't come up to our expectations at the histological examination of the gastric biopsy. The causes of group 2 were inadequate amount of the specimen in most of the carcinoma cases, and erosion and inflammation in most of the nonneoplastic lesions. Evaluating the lesion according to the revised group classification, pathologists can point out cases that require rebiopsy, but, in practice, evaluation relying on both pathologists and clinicians is essential.