非乳頭部十二指腸SM以深浸潤癌の臨床病理学的特徴—外科切除例を含めて

Clinicopathological Features of Submucosal Invasive Carcinoma in Non-ampullary Duodenal Cancer

要旨●当科で2004年9月〜2024年12月の期間に内視鏡的ないし外科的切除により診断に至った非乳頭部十二指腸癌19例20病変のうち，SM以深浸潤癌8例8病変（SM癌4病変，進行癌4病変）を抽出し，その臨床的病理学的特徴を遡及的に検討した．8例の平均年齢は77.6歳で，男性7例，女性1例であった．8病変の局在は乳頭口側が6病変，乳頭肛門側が2病変で，色調はいずれも発赤調で，辺縁に腸型腺腫成分を含む1病変を除いて白色化はみられなかった．腫瘍径中央値は37.5（10〜60）mmで10mm大の小病変にもSM以深浸潤癌がみられた．肉眼型はSMT様隆起病変が2病変，0-I型が2病変，2型が4病変で，SMT様隆起病変はいずれも頂部に腺開口部様の陥凹面を伴っていた．病理組織学的に主要組織型はすべて分化型腺癌で，細胞形質から腸型腫瘍1病変，胃腸混合型腫瘍が1病変，胃型腫瘍が5病変，分類不能型腫瘍が1病変に分類された．脈管侵襲は5病変（SM癌1病変，進行癌4病変）で陽性であった．8病変のうち，リンパ節郭清を伴う外科的切除術が行われたものは進行癌の4病変で，そのうち3病変がリンパ節転移陽性であった．SM癌と進行癌は，ともに乳頭口側に発生し胃型形質を有する傾向は類似しており，両者の関係性が強い可能性がある．今後の症例の蓄積と検討が必要である．

　Twenty nonpapillary duodenal carcinomas in 19 patients were diagnosed by endoscopic or surgical resection between September 2004 and December 2024 at our department. Among these cases, 8 SM deep invasive carcinomas（4 SM carcinomas and 4 advanced carcinomas）obtained from 8 patients were selected, and their clinical and pathological characteristics were retrospectively reviewed. The mean age of the 8 patients was 77.6 years, with 7 patients being male and 1 being female. Six lesions were found on the oral side of the nipple, whereas two lesions were on the anal side of the nipple. All lesions showed redness with no whitening, except for one lesion that contained an intestinal-type adenoma component at the margins. The median tumor diameter was 37.5mm（10−60mm）, and even a small lesion of 10mm in size showed characteristics of an SM deep invasive carcinoma. There were 2 SMT-like raised lesions, 2 0-I type lesions, and 4 type 2 lesions. All SMT-like raised lesions had a concave surface at the apex like glandular orifices. Histopathologically, the major histological types were differentiated adenocarcinomas in all cases, specifically one intestinal tumor, 1 mixed gastrointestinal tumor, 5 gastric tumors, and 1 unclassifiable tumor based on cytomorphology. Vascular invasion was positive in 5 lesions（1 SM carcinoma and 4 advanced carcinomas）. Among the 8 lesions, surgical resection with lymph node dissection was performed in 4 cases of advanced cancer, with 3 of which showing lymph node metastasis. SM and advanced carcinomas have a similar tendency to occur on the papillary orifice and to have a gastric phenotype, suggesting a strong relationship between them. Further study involving a larger number of cases is needed in the future.