鯉沼 広治

症例は41歳女性,便潜血検査陽性のため行われた大腸内視鏡検査で,虫垂開口部に径20mmの正常粘膜に覆われた弾性,硬の隆起性病変を認めた.腹部CTでは腸管内腔に突出した隆起性病変として描出され,粘膜下腫瘍の術前診断で腹腔鏡下回盲部切除術を行った.術中観察では虫垂は盲腸内に反転しており虫垂重積を疑う所見であった.病理組織学的検査では,割面で虫垂粘膜の内反を認め,筋層内には円柱状の細胞からなる腺管が内膜様間質を伴って散見され,虫垂子宮内膜症に矛盾しない所見であった.虫垂子宮内膜症を原因とした虫垂重積症は稀であるが,特徴的な内視鏡所見を把握することで,盲腸切除などの縮小手術を施行できる可能性がある.(著者抄録)

BACKGROUND: Goblet cell carcinoid (GCC) is a neuroendocrine tumor usually found in the appendix. GCCs exhibit characteristic findings with mixed endocrine-exocrine features such as staining positive for neuroendocrine markers and producing mucin. The primary GCC of the rectum is exceedingly rare. CASE PRESENTATION: A 77-year-old Japanese male presented with hematochezia. Anal tenderness and a hard mass in the anal canal were found on the digital rectal examination, and colonoscopy was performed. Colonoscopy showed an irregularly shaped mass in the anal canal. Biopsy showed mixed features including adenocarcinoma in situ, well-differentiated adenocarcinoma, and mucinous carcinoma with invasive proliferation. No metastatic lesions were found on the computed tomography scan. Pelvic magnetic resonance imaging scan showed extramural growth of a tumor on the ventral side of the rectum without invasion to the prostate. Laparoscopic abdominoperineal resection was performed. The final diagnosis was well-differentiated adenocarcinoma in the mucosa and goblet cell carcinoid from the submucosa to the adventitia of the rectum. The patient was discharged from the hospital on postoperative day 16. Six months after resection, a computed tomography scan revealed multiple metastatic lesions in the liver. Several chemotherapy regimens were given, and the patient has stable disease 27 months after surgery. CONCLUSION: We present a patient with rectal GCC with metachronous liver metastases. Since GCC grows intramurally and is biologically aggressive compared to typical carcinoid lesions, the disease is usually diagnosed at an advanced stage. The development of optimal adjuvant chemotherapy is needed for those patients.

BACKGROUND: Anti-tumor effects of radiation therapy (RT) largely depend on host immune function. Adenosine with its strong immunosuppressive properties is an important immune checkpoint molecule. METHOD: We examined how intra-tumoral adenosine levels modify anti-tumor effects of RT in a murine model using an anti-CD73 antibody which blocks the rate-limiting enzyme to produce extracellular adenosine. We also evaluated CD73 expression in irradiated human rectal cancer tissue. RESULTS: LuM-1, a highly metastatic murine colon cancer, expresses CD73 with significantly enhanced expression after RT. Subcutaneous (sc) transfer of LuM-1 in Balb/c mice developed macroscopic sc tumors and microscopic pulmonary metastases within 2 weeks. Adenosine levels in the sc tumor were increased after RT. Selective RT (4Gyx3) suppressed the growth of the irradiated sc tumor, but did not affect the growth of lung metastases which were shielded from RT. Intraperitoneal administration of anti-CD73 antibody (200 μg × 6) alone did not produce antitumor effects. However, when combined with RT in the same protocol, anti-CD73 antibody further delayed the growth of sc tumors and suppressed the development of lung metastases presumably through abscopal effects. Splenocytes derived from RT+ CD73 antibody treated mice showed enhanced IFN-γ production and cytotoxicity against LuM-1 compared to controls. Immunohistochemical studies of irradiated human rectal cancer showed that high expression of CD73 in remnant tumor cells and/or stroma is significantly associated with worse outcome. CONCLUSION: These results suggest that adenosine plays an important role in the anti-tumor effects mediated by RT and that CD73/adenosine axis blockade may enhance the anti-tumor effect of RT, and improve the outcomes of patients with locally advanced rectal cancer.

77歳男。会陰部の膨隆と疼痛を主訴とした。下部進行直腸癌に対する術前化学療法+腹腔鏡下腹会陰式直腸切断術後1ヵ月に絞扼性イレウスを発症し、緊急開腹手術を行ったが、術後に会陰部の膨隆と歩行障害を伴うほどの疼痛が出現した。腹部CTでは骨盤底への腸管の脱出はみられなかったが、会陰部皮下まで腹水の貯留を認め、会陰ヘルニアと診断して会陰ヘルニア修復術を行った。手術操作、合併症対策、ヘルニアの確実な修復の観点から経腹・経会陰の同時アプローチを選択し、前立腺から肛門挙筋で構成された3×3cmのヘルニア門をメッシュで被覆、固定した。本症例は放射線治療後であること、初回手術時に骨盤底の修復が行われていなかったことが会陰ヘルニア発症の一因と考えられた。

症例は45歳の男性で,多発血管炎性肉芽腫症に対して当院アレルギー・リウマチ科で薬剤療法を開始した.開始後12日目に下腹部痛が出現し,腹部CTにて消化管穿孔と診断し緊急手術を施行した.小腸間膜対側に10mm以下の発赤を20ヶ所認め,うち2ヶ所の穿孔部を含む3ヶ所を部分切除した.術後経過は良好で,9日目に薬剤療法を再開した小腸穿孔部の病理組織学的検査所見では,血管壁への炎症細胞の浸潤を認め,多発血管炎性肉芽腫症に伴う消化管穿孔と診断した.術後53日目に絞扼性イレウスが疑われ緊急手術を施行したが,明らかな絞扼性イレウスや穿孔の所見は認めなかった.その後の経過は良好で,薬剤療法を再開,継続中である.今回の検討から多発血管炎性肉芽腫症に伴う消化管穿孔は重症化しやすく,潰瘍性病変が多発する傾向にあり,ときに再穿孔を来すことがわかった.これらを十分理解し,患者・家族へ説明し,治療にあたることが必要である.(著者抄録)

INTRODUCTION: Metastases to the thyroid gland in patients with colorectal cancer are uncommon. We report a patient with rectal cancer who developed a metastasis to the thyroid gland. PRESENTATION OF CASE: The patient was a 45-year-old female five years status post rectal cancer resection. A thyroid lesion was detected on PET-CT scan with synchronous lung metastases. After pulmonary resection, a partial thyroidectomy was performed and pathological examination with immunohistochemical staining confirmed that the lesion was a metastasis from previous rectal cancer. She is free from recurrence two years after thyroid surgery. DISCUSSION: Colorectal metastases to the thyroid gland are usually seen with widespread disease, often with lung and liver metastases. The overall outcomes of previously reported patients with thyroid metastases were extremely poor, with most patients dying within months of diagnosis. Careful attention should be given to other sites of metastatic disease including the thyroid gland during postoperative follow-up. PET scan may be helpful to establish the diagnosis. CONCLUSION: Treatment decisions must be individualized, and depend on the presence of systemic disease. Selected patients may benefit from resection of metastases, and PET scan may be useful to identify patients who will benefit from resection.

INTRODUCTION: Internal hernias are rare after laparoscopic colorectal resections. We report a patient with an internal hernia through a defect in the transverse mesocolon following laparoscopic resection. PRESENTATION OF CASE: A 52-year-old male underwent laparoscopic colectomy for transverse colon cancer and had an unremarkable postoperative course. Thirty days postoperatively, he presented to the emergency room with sudden onset abdominal pain and vomiting. Enhanced abdominal computed tomography scan showed strangulated small intestine in the left upper abdomen. An internal hernia through the mesenteric defect created during the recent colon resection was suspected, and emergency laparotomy was performed. One hundred thirty cm of small intestine was found herniated through a mesenteric defect. After repositioning the ischemic-appearing intestine, a 5 cm defect in the transverse mesocolon was found which had not been closed during the previous laparoscopic operation. No intestinal resection was needed, and the mesenteric defect closed with non-absorbable sutures. The post-operative course was unremarkable except for paralytic ileus, which resolved without further intervention. DISCUSSION: The incidence of internal hernia through a mesenteric defect after laparoscopic colorectal resection is quite low. Therefore, routine closure of the mesenteric defect after laparoscopic colorectal resection is not required. However, a left sided defect in the transverse mesocolon might be at higher risk of causing an internal hernia on anatomic grounds. CONCLUSION: We believe that mesenteric defects should be closed after laparoscopic resection of the left side of transverse colon, regardless of their size.

＜文献概要＞症例1は57歳,男性.直腸癌(Rab)に対し腹腔鏡下低位前方切除+回腸人工肛門造設術を施行した.症例2は54歳,男性.直腸癌(Ra)に対し腹腔鏡下低位前方切除術を施行した.症例3は67歳,男性.直腸癌(Rb)に対し腹腔鏡下直腸切断術+左側方郭清を施行した.体位は砕石位で両下腿に間欠性空気圧迫装置を装着し,頭低位・右側低位としていた.手術時間は各々575分,310分,619分でいずれも術直後より左下腿の硬結・圧痛を認めた.CTで左下腿筋の造影不良・浮腫を認め下肢コンパートメント症候群と診断し,保存的治療にて軽快した.下肢コンパートメント症候群は時に後遺障害を残すことのある重篤な合併症である.文献的考察を踏まえ,筆者らの対応策を含めて報告する.

INTRODUCTION: Transverse colon resection is one of the most difficult laparoscopic procedures because of anatomic hazards such as variations in the mesenteric vascular anatomy and the complex structure of organs and surrounding membranes. METHODS: We evaluated the short-term surgical outcomes of laparoscopic transverse colon resection using a creative approach. This approach included preoperative surgical simulation using virtual surgical anatomy by CT, a four-directional approach to the mesentery, and 3-D imaging during laparoscopic surgery. RESULTS: A total of 45 consecutive patients who underwent laparoscopic resection for transverse colon cancer from June 2013 to December 2017 were enrolled in this study. All procedures were completed safely, with minor postoperative complications, including two patients with anastomotic stenosis, two with intra-abdominal phlegmon, one with delayed gastric emptying, and one with pneumonia, all treated non-operatively. There were no conversions to open resection. Operation time was 203 min (range, 125-322 min), and the estimated blood loss during surgery was 5 mL (range, 0-370 mL). The mean postoperative hospital stay was 10 days (range, 7-21 days), and no patients required readmission. CONCLUSION: Short-term surgical outcomes after laparoscopic transverse colon resection demonstrated that this creative approach was safe and feasible. The four-directional approach to the meso-transverse attachment combined with preoperative radiological simulation can facilitate laparoscopic transverse colon surgery.