病理からみた転移性消化管腫瘍

Histopathologic Interpretation of Biopsies Obtained from Metastatic Carcinomas of the Gastrointestinal Tract

要旨●転移性消化管癌の頻度は概して低く日常的に遭遇する機会が比較的低いこと，原発性癌と転移性癌の病理組織像がしばしば類似していること，転移巣が原発巣に先んじて認識される場合のあることなどから，転移性癌の生検病理組織診断は容易ではない．誤認や見逃しを避けるためには，消化管腫瘍性病変の生検病理組織診断に際して転移性癌の可能性を常に念頭に置くことが重要である．また，消化管に転移する頻度の高い癌の原発部位を認識し，それらの転移巣の病理組織学的特徴や診断に有用な免疫組織化学的陽性マーカー・陰性マーカーについて十分に理解しておく必要がある．何よりも，癌治療の既往歴などを含めた十分な臨床情報に基づく臨床病理相関の検討が必須である．

　Histopathological diagnosis of the biopsy specimens obtained from metastatic gastrointestinal carcinomas is challenging because of insufficient experience of pathologists as a result of their low incidence in daily practice, similarity in histopathologic appearances between primary and metastatic carcinomas, and recognition of metastatic foci before the diagnosis of the primary carcinoma in some cases. To avoid misinterpreting and/or overlooking the diagnosis, it should be considered that some neoplastic lesions subject to biopsy interpretation could include metastatic carcinomas. Furthermore, it is important to understand the primary sites of carcinomas that have a predilection for gastrointestinal metastasis and the histopathologic features of their metastatic foci in the gastrointestinal tract, including useful positive and/or negative immunohistochemical markers for diagnosis. Finally, clinicopathological correlation based on adequate clinical information, such as history of cancer treatment, is required.