遠隔転移再発を認めたPG type隆起型下部直腸T1b癌の1例

Polypoid Growth Type Deep Submucosal Carcinoma of the Lower Rectum Recurring as Distant Metastasis after Curative Resection, Report of a Case

要旨●患者は40歳代，女性．血便精査目的に施行した大腸内視鏡検査にて，下部直腸に30mm大の0-Is型腫瘍を認めた．拡大内視鏡検査と超音波内視鏡検査を施行しcT1b癌と診断した．CTにてリンパ節腫大や他臓器への転移所見を認めず，cT1N0M0と診断し超低位前方切除術を施行した．最終診断はpT1b，pN0，pM0，pStage Iで経過観察となった．初回手術より6か月後に肺転移再発したため，化学治療後肺切除を施行した．術後補助化学療法を継続したが，38か月後にリンパ節再発，脳転移再発し44か月後に永眠となった．大腸T1癌の外科手術後の予後は良好だが，Stage Iであっても早期に再発し死に至ることもあるため慎重な経過観察行うことが肝要である．

　A female in her 40s was hospitalized with 1-year history of hematochezia. Colonoscopy revealed a sessile lesion（30mm）in the lower rectum（Rb）. With magnifying colonoscopy and endoscopic ultrasonography, this tumor was diagnosed as clinical（c）T1b carcinoma（submucosal invasion depth ≧1,000m）. Contrast-enhanced computed tomography revealed no lymph node metastasis or distant metastasis. We performed ultra-low anterior resection（D2）based on cT1N0M0 diagnosis and considered surgery to be curative. The final diagnosis was Rb, 0-Is, tub2>tub1, pTlb, INF b, Ly1a, V0（VB）, BD2, pN0, pM0, and pStage I without adjuvant chemotherapy. Owing to the recurrence of pulmonary metastasis subsequent to 6 months of the primary surgery, we performed lobectomy after chemotherapy. Then, postoperative adjuvant chemotherapy was continued ; however, lymph node recurrence with brain metastasis occurred after 38 months. The patient died 44 months after the primary surgery. Although surgical outcomes for T1 colorectal carcinoma are considered good, careful observation is warranted during postoperative follow-up of Rb carcinoma. Therefore, physicians should contemplate further follow-up of aggressive cases even after curative resection, as in this case of stage I disease.