原発巣切除後長期観察中に肝転移を発症した胃カルチノイドの1例

Liver Metastasis from the Patients Who Underwent Gastrectomy for Primary Gastric Carcinoid Tumor after Long Surveillance, Report of a Case

要旨　患者は62歳，女性で，1974年4月，近医の胃X線検査にて胃体部の隆起性病変を指摘され，当院の上部消化管内視鏡検査による生検にてカルチノイド腫瘍と診断された．胃亜全摘術が施行され，切除後順調に経過していたが，1982年9月ごろより顔面紅潮，皮膚搔痒感や息切れなど，いわゆるカルチノイド症候群の症状および右季肋部痛が出現してきた．腹部超音波検査にて，肝S5，7，8の領域に及ぶ巨大腫瘍が指摘され，更に尿中5-HIAAの上昇も認められ，胃カルチノイド腫瘍からの肝転移と診断された．本症例は，胃切除時組織所見では，比較的均一な円形の核を持つ腫瘍細胞が索状，あるいは一部腺腔構造をとりながら増殖する古典的カルチノイド腫瘍であったが，一部に大型の核から構成される部分も混在し，同部では核の大小不同や分裂像もわずかに認められた．このために，非常に緩徐ではあるが長期経過後に肝転移を来した可能性が考えられた．カルチノイド腫瘍は比較的まれな疾患であるため，発生母地や組織学的悪性度，更にその臨床的取り扱いについてもいまだ不明確な部分も多いが，胃癌同様の慎重な臨床対応が必要と考えられた．

　A 62-year-old female was found to have a polypoid lesion of which 10 mm in size on the lower gastric body by the health check in previous hospital on april, 1974. A small submucosal tumor with cental depression was detected by endoscopic examination in our hospital. The patient was admitted to our surgical division to undergo gastrectomy because carcinoid tumor was histologically confirmed by biopsy. On admission, the patient was in good condition and laboratory data including endocrinological findings were within normal limits.

　The patient received subtotal gastrectomy with lymph node dissection. Gastric carcinoid tumor invading submucosa was diagnosed on the resected specimen. Although the tumor was mainly composed of uniform cells with small round nuclei so called classical type carcinoid tumor, the cells with large round nuclei with a few mitosis were also shown in a part.

　Endocrine cell tumor has been classified as classical type carcinoid and endocrine cell carcinoma. Classical type carcinoid is generally composed of uniform cells with small round nuclei which is low grade atypia and less invasive, namely low malignancy biologically. Regardless of classical type carcinoid, however, there are some reports that metastasis from the patients with that tumor is led after long surveillance. In our case, the cells with large round nuclei and a few mitosis were recognized in a part of the tumor. The existence of these findings might lead liver metastasis after 8 year periods.

　Although classical type carcinoid is basically low malignant tumor, our experience suggests that this tumor should be carefully treated as gastric cancer.