大腸カルチノイドの診断と治療

Carcinoid Tumor of the Colon: Diagnosis and Treatment

要旨　1988年末までの19年間に国立がんセンター病院で経験された大腸カルチノイドは43症例43病変で，うち42例は直腸に認められた．病変が大きくなるにしたがい，病変の立ち上がりもなだらかなものからくびれをもつものが多くなり，また陥凹を有する病変の頻度が高くなった．陥凹を有する病変では固有筋層浸潤，リンパ節転移，肝転移など悪性カルチノイドの割合が高かった．生検の陽性率は95％であった．遡及的検討が可能であった4例4病変のうち形態・大きさに変化を認めなかったものが2例，4年間に7～10mmと変化し，粘膜下層まで浸潤し転移を認めないもの1例，5年7か月間に13～25mmと増大し中心陥凹の出現を認め，固右筋層への浸潤と肝転移を伴って死亡したものが1例あった．カルチノイドによる死亡はこの肝転移を伴った1例と，粘膜下層まで浸潤した1例の計2例で，合併した直腸癌による死亡が1例あった．治療は内視鏡的あるいは外科的ポリペクトミーなどの局所切除により腫瘍の切除が可能なものが多いが，悪性のカルチノイドに対しては癌に準じた根治手術が必要であり，その悪性の診断指標には大きさと陥凹の有無が重要な所見と考えられた．

　We experienced 43 lesions of carcinoid tumor of the colon at the National Cancer Center Hospital during 19 years until the end of 1988. Forty-two lesions were located in the rectum. Death cases due to carcinoid tumor included a case with invasion to the proper muscle and hepatic matastasis, a case with submucosal invasion, and another case complicated with rectal cancer. The larger the lesion, the more frequently there was a sharp area rather than smooth transition at the take-off from the surrounding mucosa and a depression. The frequency of malignancy, such as the one with invasion into the proper muscle, lymphnode metastasis, or hepatic metastasis, was higher among the cases with a depressed lesion. Ninety-five percent of the biopsy specimens were positive for carcinoid tumor. Follow-up examinations were possible in 4 cases: no changes in shape and size in 2 cases, increased size from 4 to 7 mm with invasion to the submucosa but without remote metastasis in 1 case, increased size from 13 to 25 mm with a central depression, invasion to the submucosa as well as hepatic metastasis resulting in death in 1 case. In most cases resection (such as polypectomy) of the tumor was possible either endoscopically or surgically. Malignant carcinoid tumor, however, necessitated curative surgery as applied to carcinoma. The tumor size and the presence of depression were considered important diagnostic indices associated with malignancy.