胃胎児消化管類似癌と肝様腺癌の臨床病理学的特徴

Pathological Features of Stomach Adenocarcinoma with Enteroblastic Differentiation and Hepatoid Adenocarcinoma

要旨●胎児消化管類似癌（ACED）成分を伴う早期胃癌31例の病理組織像と臨床病理学的特徴を解析した．ACEDに相当する淡明な細胞から成る分化型腺癌あるいは充実型癌成分に加えて，一般型分化型腺癌（tub/pap）成分は高頻度に混在し，肝様腺癌（HAC）成分もが混在することがあるが，いずれも脈管侵襲やリンパ節転移が高頻度の高悪性度の癌であることが示された．これらは，retro differentiationを来した胎児消化管関連癌として包括可能で，分化型腺癌（tub/papまたは分化型ACED）として発生し，発生時または発育過程で胎児消化管の性格を獲得し，一部は充実性に増殖すると考えられる．ただし，組織型の亜分類の必要性については今後の課題である．

　The histology and clinicopathological features of 31 early stage gastric cancers with ACED（adenocarcinomas having enteroblastic differentiation）components were analyzed. In addition to the differentiated or solid component of ACED, the commonly differentiated adenocarcinoma（tub/pap）component is frequently mixed, including the HAC（hepatoid adenocarcinoma）component. Moreover, they have all been known to be highly aggressive and are characterized by a high frequency of lymphovascular invasion and lymph node metastasis.

　They can be included in fetal gastrointestinal tract-related carcinomas of the same lineage that have caused retrodifferentiation. They form as differentiated adenocarcinoma, acquiring fetal gastrointestinal tract characteristics at the time of development or during development, and partially growing into a solid tumor. Thus, further histological subclassification of these tumors is necessary.