川辺 則彦

The natural history of intracholecystic papillary neoplasm (ICPN), especially the speed of growth from small benign to a carcinomatous lesion, is quite unrevealed. Here, we report an extremely rare case of ICPN, in which the papillary lesion was observed transforming from small and benign to malignant using abdominal ultrasound (AUS) over 2 years during routine health checks. A 44-year-old man underwent a routine health check-up. The initial AUS showed a small sessile polyp in the gallbladder, which enlarged slightly at the next AUS, a year later. In the third year, the polypoid lesion enlarged markedly, with a maximum diameter of 10 × 9 × 7 mm. Therefore, a laparoscopic cholecystectomy was performed. Microscopically, the 10 mm tumor had intracytoplasmic mucus, and a clear cytoplasm compatible with gastric-type features. Immunohistochemical analysis showed positive staining of atypical cells for MUC6 and PAS. These findings led to the diagnosis of ICPN with high-grade intraepithelial neoplasia of the gastric type. In conclusion, sessile polyps with rapid growth might be a crucial finding in the early stage of ICPN.

OBJECTIVES: Heterotopic ossification (HO), which occurs when bone tissue forms outside the skeleton, is extremely rare in rectal cancer. Adenocarcinoma is the histological type of all reported primary colorectal cancers with HO. However, in the present case, we observed areas of adenocarcinoma with squamous cell carcinoma-like differentiation. Here we conducted histopathological and immunohistochemical analyses to identify the mechanisms of HO development, to differentiate between adenocarcinoma and squamous cell carcinoma-like phenotypes, and to understand the associated prognostic implications. CASE REPORT: A 62-year-old woman was admitted to our hospital with symptoms of intermittent hematochezia without abdominal pain. Colonoscopy revealed stenosis with a protuberant mass in the rectum. Abdominopelvic contrast-enhanced computed tomography showed irregular wall thickness of the rectum, multiple lymph node metastases, and liver metastases. The rectal tumor exhibited calcified deposits with marked hyperintensity. We then performed Hartmann's operation and D3 lymph node resection. The biopsy specimen revealed tubular and solid adenocarcinoma nests and squamous carcinoma-like components over a necrotic extent without secreted mucin. She received chemotherapy (mFOLFOX6 with bevacizumab) as the first option and is alive 5 months after surgery. CONCLUSION: To the best of our knowledge, this is the first case of heterotopic ossification in a primary rectal cancer with squamous cell carcinoma-like differentiation that was surgically resected. This case suggests that BMP-2 transformed fibroblasts and pluripotent stem cells into osteocytes. We conclude that the squamous cell carcinoma-like lesion was squamous metaplasia of adenocarcinoma.

症例は72歳、男性。2009年より慢性膵炎にて薬物治療中、腹部USにて膵管拡張を指摘され当院紹介となった。採血上、腫瘍マーカーは正常範囲内であった。造影CTでは、膵体部に尾側膵管の拡張を伴う直径30mmの乏血性腫瘍を認めた。同腫瘍は総肝動脈・脾動脈・腹腔動脈に浸潤が疑われた。EUSでは直径29×24mmの低エコー腫瘍を認めた。ERCPでは膵体部主膵管の途絶を認め、膵液細胞診では腺癌を疑う結果であった。局所進行切除不能膵体部癌と診断し、GnPを施行した。GnP6コース施行後のCTにて腫瘍は縮小傾向を認めた。PET-CTでは、同腫瘍にSUVの軽度集積亢進を認めるも、血管周囲には集積を認めなかった。以上より、根治切除可能と判断し手術を施行した。手術は腫瘍周囲の軟部組織の迅速病理検査を行い、悪性所見のないことを確認した上で脾臓合併膵体尾部切除術を行った。病理組織学的にtubular adenocarcinomaの所見で、腫瘍は全体の約30%程度の残存で、組織学的効果判定はGrade2であった。(著者抄録)

今回、術前から肝動脈分岐形態と膵頭部領域腫瘍との位置関係に留意しながら肝動脈合併切除(非再建)PDを施行し、根治術が可能であった2症例を報告する。症例1:患者は73歳、男性。黄疸を主訴に来院し、術前精査にて遠位胆管癌と診断された。術前造影CTにて右肝動脈は通常どおり胆管後面を走行しており、胆管腫瘍と周囲リンパ節内を貫通しており浸潤が示唆された。左肝動脈は肝十二指腸間膜左縁を走行しておりintactであった。術中所見では右肝動脈は腫瘍と周囲リンパ節に一塊となって巻き込まれており、右肝動脈温存は不可能であった。右肝動脈をクランプ後、エコーにて肝右葉内の動脈血流が左肝動脈から肝門板を介して流入していることを確認し、右肝動脈合併切除非再建PDを施行した。術後、肝動脈血流に問題なく、また病理組織からもR0切除可能であった。症例2:患者は65歳、男性。黄疸を主訴に来院し、術前精査で総肝動脈にencasementを認める膵頭部癌(BR)と診断された。自験例では右肝動脈はSMAから、左肝動脈は左胃動脈から分岐しており、総肝動脈を切離しても肝動脈血流は十分保持されると判断し、総肝動脈門脈合併亜全胃温存膵頭十二指腸切除術(SSPPD)を施行した。術中所見では総肝動脈、胃十二指腸動脈をテストクランプ後も肝動脈血流は問題なく総肝動脈は非再建とした。術後肝酵素の上昇や肝梗塞は認めず、病理学的にもR0切除が可能であった。(著者抄録)

The case was a 72-year-old man who had been on medication due to chronic pancreatitis since 2009 and was referred to our hospital because dilation of the main pancreatic duct was shown by abdominal ultrasonography. The contrast CT scan of the abdomen showed a 30 mm in size, poorly enhanced tumor at the body of the pancreas, which was suspected to invasion the celiac artery, common hepatic artery, and splenic artery. EUS showed a hypoechoic tumor with a diameter of 29× 24 mm. ERCP showed disruption of the pancreatic duct in the body of the pancreas, and cytological examination of the pancreatic juice showed a suspicious positive result. We diagnosed unresectable locally advanced pancreatic cancer in the body of the pancreas and underwent chemotherapy(gemcitabine plus nab-paclitaxel: GnP). Contrast-enhanced CT after 6 courses of GnP showed tumor shrinkage. FDG-PET/CT revealed a slightly in fluorine-18-deoxyglucose(FDG)accumulation in the tumor, but no accumulation around the blood vessels. Based on the above, it was judged that the tumor was possible radical resection, and surgery was performed. Intraoperative frozen section examination revealed no malignant findings in the tissues surrounding the main artery near the pancreatic body cancer, and distal pancreatectomy was performed. Histopathologically, the tumor showed findings of tubular adenocarcinoma, and the histological response to neoadjuvant therapy was Grade 2. We report a case in which conversion surgery was possible by chemotherapy.

BACKGROUND: The association between pancreatic fistula (PF) after pancreaticoduodenectomy (PD) and preoperative exocrine function is yet to be elucidated. This study aimed to evaluate the association between the preoperative results of the 13C-trioctanoin breath test and the occurrence of PF, showing the clinical relevance of the breath test in predicting PF. METHOD: A total of 80 patients who underwent 13C-trioctanoin breath tests prior to PD from 2006 to 2018 were included in this study. Univariate and multivariate analyses were conducted to reveal the preoperative predictors of PF, showing the association between 13C-trioctanoin absorption and PF incidence. RESULTS: Among 80 patients (age, 68.0 ± 11.9 years, 46 males and 34 females; 30 pancreatic ductal adenocarcinoma [PDAC]/50 non-PDAC patients), the incidence of PF was 12.5% (10/80). Logistic regression analysis results revealed that the frequency of PF increased significantly as the 13C-trioctanoin breath test value (Aa% dose/h) increased (odd's ratio: 1.082, 95% confidence interval: 1.007-1.162, p = 0.032). Moreover, the optimal cutoff value of the preoperative fat absorption level to predict PF was 38.0 (sensitivity, 90%; specificity, 74%; area under the curve, 0.78; p = 0.005). Indeed, the incidence of PF was extremely higher in patients whose breath test value was greater than 38.0 (33%, 9/27) compared with that in patients with values less than 38.0 (1.8%, 1/53). CONCLUSIONS: Favorable preoperative fat absorption evaluated using the 13C-trioctanoin breath test is a feasible and objective predictor of PF after PD.

The two patterns of pathogenesis for pancreatic colloid carcinoma are reported; (1) progression from ordinary ductal adenocarcinoma, a subtype of invasive pancreatic ductal carcinoma, and (2) progression from papillary adenocarcinoma derived from intraductal papillary mucinous neoplasm (IPMN) or mucinous cystic neoplasm (MCN). Whether these two conditions are the same disease remains controversial. Case Report 1. An 81-year-old woman was evaluated for an increased carbohydrate antigen 19-9 (CA19-9) value (130 U/mL) detected at 4-year follow-up after distal pancreatectomy for IPMN. Based on the image findings, a local recurrence of IPMN was diagnosed, and the patient underwent a remnant total pancreatectomy. Histopathologic findings showed marked mucus production from the tumor, also noteworthy because mucous nodule formation occurs in more than 80% of tumor. Fibrosis around the mucous cavity was noted, and a low papillary lesion was found in part of the cyst wall, which was contiguous to a flat, basal area; its nucleus was enlarged and heterogeneous in size, which is considered to be a component of intraductal papillary mucinous (IPMC). Therefore, the patient was diagnosed with pancreatic colloid carcinoma derived from IPMN. Case report 2 a 71-year-old man was evaluated for jaundice. Based on the image findings, a diagnosis of pancreatic head cancer was made, and a substomach preserving pancreaticoduodenectomy was performed. Histologically, marked mucus production and floating cuboidal masses of atypical cells without mucinous nodules were seen. Mucinous nodule formation is observed in more than 80% of tumor, but there was no IPMN component, which led to the diagnosis of pancreatic colloid carcinoma. In conclusion, there might be two types of colloid carcinoma of the pancreas, and further study is needed to determine whether these diseases are truly the same or not.

BACKGROUND: Performing major hepatectomy for patients with marginal hepatic function is challenging. In some cases, the procedure is contraindicated owing to the threat of postoperative liver failure. In this case report, we present the first case of marginal liver function (indocyanine green clearance retention rate at 15 min [ICGR15]: 28%) successfully treated with right hepatectomy, resulting in total caudate lobe preservation. CASE PRESENTATION: A 71-year-old man was diagnosed with sigmoid colon cancer with three liver metastases (S5, S7, and S8). All of metastatic lesions shrunk after chemotherapy, but his ICGR15 and indocyanine green clearance rate (ICGK) were 21% and 0.12, respectively. Moreover, the remnant liver volume was only 39%. Therefore, portal venous embolism (PVE) of the right portal vein was suggested. Portography showed divergence of the considerably preserved right caudate lobe branch (PV1R) from the root of the right portal vein. The liver function was reevaluated 18 days after PVE was suggested. During this time, the ICGR15 (21-28%) and ICGK rate (0.12-0.10) deteriorated. The right caudate lobe was significantly enlarged; thus, a total caudate lobe-preserving hepatectomy (TCPRx) was performed. Patients eligible for TCPRx included those with (1) hepatocellular carcinoma or metastatic liver cancer, (2) no tumor in the caudate lobe, (3) marginal liver function (ICG Krem greater than 0.05 if TCPRx was adapted; otherwise, less than 0.05) and Child-Pugh classification category A, and (4) preserved PV1R and right caudate bile duct branch. The procedure was performed through (A) precise estimation of the remnant liver volume preoperatively, (B) repeated intraoperative cholangiography to confirm the biliary branch of the right caudate lobe (B1R) conservation, and (C) stapler division of posterior and anterior Glisson's pedicles laterally to avoid injuries to the PV1R and B1R. CONCLUSIONS: Right hepatectomy with total caudate lobe preservation, following PVE, was a safe and viable surgical technique for patients with marginal liver function.

胆道癌登録は本邦における胆道癌(肝門部領域胆管癌、遠位胆管癌、胆嚢癌、十二指腸乳頭部癌)症例の疫学調査を行うことにより、胆道癌に関する研究ならびに診療の進歩・知識の普及を図ることを目的としている。実際に2016年から2018年の累計登録数は胆管癌:3,937例、胆嚢癌:2,432例、乳頭部癌:1,229例(2021年3月時点)であり、予後も含めた登録項目の完全入力(欠落なし)率は88.5%にも達し、米国のSEER、NCDBより高率であった。今後、2022年度より本登録システムは、一般社団法人National Clinical Database(NCD)が実施するデータベース事業に移管することが決定しており、さらなる症例登録数の増加と完全入力率の改善が期待される。胆道癌登録は世界的にも類をみない、ビッグデータであり、検討項目においても、病歴から手術所見、切除病理組織所見に至るまで極めて詳細かつ正確なデータをもとに臨床検討がなされている。一方、これらの項目を入力する臨床医は忙しい日常の中で入力に多大の労力を費やしているのも現実であり、NCD実装に伴いこれらの労力が少しでも軽減されることを期待したい。(著者抄録)

Caroli病は末梢肝内胆管の多発性嚢状拡張を示す疾患であり、肝線維化を伴わない先天性肝内胆管拡張症はCaroli病とよばれる一方、肝線維化・肝硬変を伴う場合はCaroli症候群と分類される。Caroli病の場合、その主症状は胆管炎に起因するものが多く、右季肋部痛、発熱、黄疸を主訴とすることが多い。Caroli症候群ではグリソン鞘の線維化、門脈圧亢進症に伴う症状が主体となり、肝脾腫大に伴う腹部の痛みや腹部膨満感などが主症状となる。診断にはCT、超音波によるcentral dot signが有用であるとされていたが、近年、MRCPにおけるsaccular and fusiform featuresとperipheral funnel-shaped signがより診断率が高いことが報告された。進行すると比較的高率に胆管癌を発症するため、適切な診断のもと、内科的治療から肝移植まで包括的な治療を行うことが肝要である。(著者抄録)