胃腺腫と分化型癌との病理学的鑑別—腸型腺腫

Pathological Differential Diagnosis of Adenoma and Differentiated-type Adenocarcinoma of the Stomach: Gastric Adenoma with an Intestinal Phenotype

要旨　胃腺腫はほとんどが腸型形質を示す病変である．病理診断においては，腸型腺腫と分化型癌の鑑別診断はしばしば苦慮するところである．今回，筆者らは腸型形質を呈する胃腺腫63病変，低異型度癌50病変，高異型度癌43病変を対象に，臨床病理学的・免疫組織学的特徴を解析した．腺腫と高異型度癌は臨床病理学的・免疫組織学的にも明らかに異なる腫瘍であったが，腺腫（高異型度）と低異型度癌は類似した腫瘍であり，鑑別診断が困難であることが示唆された．腺腫と低異型度癌の鑑別は，HE染色像での核形態や核配列を重視して診断することが重要であると考えられた．

　Most gastric adenomas express an intestinal phenotype. It is difficult for general pathologists to make a differential diagnosis between adenoma and differentiated-type adenocarcinoma with an intestinal phenotype. The aim of this study was to clarify the clinicopathological and immunohistochemical features between adenoma and differentiated-type adenocarcinoma with an intestinal phenotype. We studied 63 gastric adenoma lesions, 50 low-grade gastric adenocarcinoma lesions, and 43 high-grade gastric adenocarcinoma lesions. No significant differences were observed in the clinicopathological and immunohistochemical features between gastric adenomas and low-grade gastric adenocarcinomas. It is important to consider the nuclear shape, nucleus−cytoplasm ratio, and disorder in polarity to make a differential diagnosis between gastric adenoma and differentiated-type gastric adenocarcinoma.