生検診断が困難であった胃の高分化型腺癌の1例

Highly Differentiated Adenocarcinoma of the Stomach: Report of a Case with Difficulty in Pathologic Diagnosis on Biopsy

要旨　患者は65歳，男性．体重減少を主訴とし某医院を訪れ，当院を紹介された．胃X線，内視鏡検査にて，体上部前壁になだらかな立ち上がりを示し，黄白色の白苔が点状に付着する隆起病変を認め，Borrmann 1型胃癌と診断した．しかし計3回の生検組織検査では，腺管の細胞，構造異型が乏しく，悪性と診断できなかった．臨床的に悪性を否定しきれないため，胃全摘術を施行した．切除胃肉眼所見では体上部前壁に大きさ4×3×0.5cmの全体に幾分発赤した病巣を認めた．病巣範囲は不明瞭であるが，発赤した範囲と考えられた．組織学的にも癌と診断するのに苦慮したが，腺管周囲の炎症性細胞浸潤が著明なこと，固有筋層まで浸潤していることより，高分化型腺癌（tub₁，INF β，pm，ly₀，v₀，n(－)）と診断した．本病巣は中間帯領域に存在していた．病巣周囲粘膜にはPAS-AB染色での定型的腸上皮化生が主体をなし，また，病巣内増生腺管にもPaneth顆粒を有する腸上皮化生を多数認めた．所々に幽門腺または粘液腺より成る粘膜下異所腺を認めた．この異所腺にも腸上皮化生が認められ，異所腺からの癌化も否定しえない問題と考えられた．

　The patient, a 65 year-old man, was referred to our hospital because of marked weight loss. Roentgenographic and gastrofiberscopic examinations revealed an elevated lesion with gentle sloping up, covered with yellowish-white spots of coating, on the anterior wall of body of the stomach. A diagnosis of Borrmann type 1 gastric carcinoma was made. On all three occasions of repeated biopsy, nevertheless, glandular tubules of the lesion were scanty of cytomorphologic and structural atypia. Hence, a diagnosis of malignancy was hardly warranted, but a total gastrectomy was performed since the possibility of a malignant neoplasm could not be clinically ruled out. A lesion measuring 4 × 3 × 0.5 cm, somewhat reddened over the entire area, on the anterior wall of the corpus ventriculi was noted on gross examination of the resected specimen. The lesion was poorly demarcated and appeared to be confined to the erythematous area. Microscopic findings were also not convincingly diagnostic, but because of pronounced inflammatory cell infiltration around proliferating glandular tubules with involvement as far as the muscularis propria a diagnosis of highly differentiated adenocarcinoma (tub₁ INF β, pm, ly₀, v₀, n (－)) was made.

　The lesion was situated in the intermediate zone. Sections with PAS-alcian blue stain revealed a predominant typical intestinal epithelial metaplasia in the mucoua surrounding the lesion and frequent occurrence of such metaplasia with Paneth granules in the proliferating glandular tubule cells within the lesion. Submucosal ectopic glands composed of pyloric and mucous gland tissues were also seen in places. Intestinal epithelial metaplasia was evident with these ectopic glandular tissues, hence suggesting potential malignant changes from the ectopic glands.