予後不良な経過をたどった十二指腸粘膜下層浸潤癌の1例

Laterally Spreading Duodenal Cancer with Slight Submucosal Invasion Accompanied with Concurrent Lymph Node Metastasis, Report of a Case

要旨●患者は70歳代，女性．近医での内視鏡検査で十二指腸下行部内壁側を主座とする約80mm大の隆起性病変を指摘された．病変は主乳頭を完全に巻き込んでおり，主乳頭を含めたESDによる一括切除を行った．術後病理組織学的検査では，ごくわずかな領域において粘膜下層浸潤（100μm）ならびにリンパ管浸潤を指摘された．ESDから2か月後に追加外科手術を施行したものの，術後5か月後の造影CTで全身転移を指摘され，術後9か月後に死亡した．十二指腸癌は他消化管癌と比較して，高い生物学的悪性度を有する可能性が示唆される．そのため，術前に高い確診度で低異型度腫瘍と診断する場合を除いては，確実な一括切除と信頼性の高い病理組織学的診断を考慮する必要がある．

　A female patient in her 70s with duodenal cancer was referred to our hospital. Esophagogastroduodenoscopy revealed an 80-mm flat elevated lesion located on the inner wall of the second part of the duodenum that completely involved the major papilla. ESD（endoscopic submucosal dissection）was performed and the lesion was resected as a single piece that included a part of the major papilla. Pathological examination of the resected specimen showed moderately differentiated adenocarcinoma limited to the mucosa in most parts of the lesion ; however, cancer cells invaded the submucosal layer with an invasion depth of 100μm in a small area that involved lymph ducts. Two months after ESD, pylorus-preserving pancreatoduodenectomy combined with extended lymph node dissection was additionally performed. The postoperative histopathological examination revealed lymph duct involvement in the regional lymph nodes. While the postoperative clinical course was uneventful, systematic metastasis was discovered 5 months after surgery. The patient died 9 months after surgery. Due to its rarity, the natural history of duodenal cancer has remained unclear. In this case, even a lesion with only a small, localized area of submucosal invasion developed systemic metastasis, indicating the high malignant potential of duodenal cancer.