笹沼 英紀

PURPOSE: We previously reported that acoustic radiation force impulse (ARFI) with concomitant administration of perfluorobutane as an ultrasound contrast agent (UCA)-induced arrhythmias at a mechanical index (MI) of 1.8 or 4.0 in a rabbit model. The present study identified the location of arrhythmias with a MI < 1.8 using a new system that can transmit ARFI with B-mode imaging. METHODS: Under general anesthesia, six male Japanese white rabbits were placed in a supine position. Using this system, we targeted ARFI to the exact site of the heart. ARFI exposure with MI 0.9-1.2 was performed to the right or left ventricle of the heart 2 min after UCA injection. RESULTS: ARFI with a MI lower than previously reported to rabbit heart evoked extrasystolic waves with single UCA infusion. Arrhythmias were not observed using ARFI without UCA. Extrasystolic waves were observed significantly more frequently in the right ventricle group than in the left ventricle group, with arrhythmias showing reversed shapes. No fatal arrhythmias were observed. CONCLUSION: ARFI applied to simulate clinical conditions in rabbit heart evoked extrasystolic waves with single UCA infusion. The right ventricle group was significantly more sensitive to ARFI exposure, resulting in arrhythmias, than the left ventricle group. The shapes of PVCs that occurred in the right ventricle group and the left ventricle group were reversed. Ultrasound practitioners who use ARFI should be aware of this adverse reaction, even if the MI is below the previously determined value of 1.9.

症例は37歳,女性.25歳で偶発的に膵体尾部に嚢胞性病変を指摘され,精査目的に当院消化器内科に紹介された.腹部造影CTとMRI検査では膵尾部に約5cmの嚢胞性腫瘤を認め膵粘液性嚢胞腫瘍(mucinous cystic neoplasm:MCN)が疑われたが,経過観察の方針となった.32歳時の第2子妊娠を契機に経過観察が一時中断となり,5年後の37歳に再診した.嚢胞性腫瘤は多房化し,大きさ6cmへの増大を認め,血清CA19-9の上昇を伴ったことから手術目的に消化器外科紹介となった.腹腔鏡下膵体尾部脾摘術を施行し,術後経過は良好で術後11日目に退院した.病理組織像では卵巣様間質を認め,微小浸潤を伴った膵粘液性嚢胞腺癌の診断であった.MCNの自然史を解明するには長期経過観察例の集積が必要である.(著者抄録)

BACKGROUND: Pancreatojejunostomy (PJ) is one of the most difficult and challenging abdominal surgical procedures. There are no appropriate training systems available outside the operating room (OR). We developed a structured program for teaching PJ outside the OR. We describe its development and results of a pilot study. METHODS: We have created this structured program to help surgical residents and fellows acquire both didactic knowledge and technical skills to perform PJ. A manual was created to provide general knowledge about PJ and the specific PJ procedure used in our institution. Based on questionnaires completed by trainers and trainees, the procedure for PJ was divided into twelve steps and described in detail. After creating the manual, we developed organ models, needles and a frame box for simulation training. Three residents (PGY3-5) and three fellows (PGY6 or above) participated in a pilot study. Objective and subjective evaluations were performed. RESULTS: Trainees learn about PJ by reading the procedure manual, acquiring both general and specific knowledge. We conducted simulation training outside the OR using the training materials created for this system. They simulate the procedure with surgical instruments as both primary and assistant surgeon. In this pilot study, as objective assessments, the fellow-group took less time to complete one anastomosis (36 min vs 48 min) and had higher scores in the objective structured assessment of technical skill (average score: 4.1 vs 2.0) compared to the resident-group. As a subjective assessment, the confidence to perform a PJ anastomosis increased after simulation training (from 1.6 to 2.6). Participants considered that this structured teaching program is useful. CONCLUSION: We developed a structured program for teaching PJ. By implementing this program, learning opportunities for surgical residents and fellows can be increased as a complement to training in the OR.

膵癌においては外科治療が治癒の期待できる唯一の治療法であるが,手術侵襲についても十分に考慮されるべきである.2000年代以降,膵癌に対する化学療法・放射線治療の治療成績が目覚ましく向上する中で,集学的治療の一環として拡大手術の最新のエビデンスと位置づけを理解することは重要である.PV/SMV合併切除は比較的安全に施行可能で,R0切除になる場合に考慮される術式であり,術後治療が行えた場合は良好な予後が期待できる.動脈合併切除の意義は乏しいが,長期生存の報告もある.腹腔動脈合併切除を伴う尾側膵切除は合併症率が高く,症例・施設を厳選して行われるべきである.拡大リンパ節郭清の意義は否定されたが,至適リンパ節郭清範囲は未だ定まっていない.(著者抄録)

BACKGROUND: Familial adenomatous polyposis (FAP) is characterized by the presence of hundreds to thousands of colonic polyps, and extracolonic manifestations are likely to occur. Pancreatic tumors are rare extracolonic manifestations in patients with FAP, among which solid-pseudopapillary neoplasm (SPN) are extremely rare. We report here a patient with an SPN of the pancreas found during the follow-up of FAP. CASE PRESENTATION: A 20-year-old woman was diagnosed with FAP 3 years previously by colonoscopy which revealed less than 100 colonic polyps within the entire colon. She complained of left upper abdominal pain and a 10-cm solid and cystic pancreatic tumor was found by computed tomography scan. Solid and cystic components within the tumor were seen on abdominal magnetic resonance imaging. Simultaneous laparoscopic resection of the distal pancreas and subtotal colectomy was performed. Histopathological findings confirmed the pancreatic tumor as an SPN without malignancy. Abnormal staining of beta-catenin was observed by immunohistochemical study. Multiple polyps in the colorectum were not malignant. Molecular biological analysis from peripheral blood samples revealed a decrease in the copy number of the promoter 1A and 1B region of the APC gene, which resulted in decreased expression of the APC gene. CONCLUSIONS: A rare association of SPN with FAP is reported. The genetic background with relation to beta-catenin abnormalities is interesting to consider tumor development. So far, there are few reports of SPN in a patient with FAP. Both lesions were treated simultaneously by laparoscopic resection.

A 48-year-old man underwent skin grafting from the left inguinal region to the left forearm one month previously. He noticed abdominal discomfort after discharge and was admitted to another hospital because of progression of abdominal pain and a decreased level of consciousness. An enhanced CT scan revealed extensive portal venous thrombosis. Lower gastrointestinal bleeding developed the following day, and he was transferred to our hospital and diagnosed with superior mesenteric venous thrombosis. Enhanced CT showed no intestinal necrosis. Anticoagulant therapy was started and the thrombosis had almost resolved 40 days later. However, after starting oral intake, the patient developed vomiting. Small bowel radiographs and 3D-CT showed significant proximal intestinal stenosis. Small bowel resection was performed on the 59th day after transfer. The pathological diagnosis was ischemic enteritis with venous thrombosis. The patient was discharged 20 days after intestinal resection and he has had no recurrence of symptoms. In this case, 3D-CT was useful to determine the range of intestinal stenosis and the required area of resection.

Traumatic injury to the main pancreatic duct requires surgical treatment, but optimal management strategies have not been established. In patients with isolated pancreatic injury, the pancreatic parenchyma must be preserved to maintain long-term quality of life. We herein report a case of traumatic pancreatic injury with main pancreatic duct injury in the head of the pancreas. Two years later, the patient underwent a side-to-side anastomosis between the distal pancreatic duct and the jejunum. Eleven years later, he presented with abdominal pain and severe gastrointestinal bleeding from the Roux limb. Emergency surgery was performed with resection of the Roux limb along with central pancreatectomy. We attempted to preserve both portions of the remaining pancreas, including the injured pancreas head. We considered the pancreatic fluid outflow tract from the distal pancreatic head and performed primary reconstruction with a double pancreaticogastrostomy to avoid recurrent gastrointestinal bleeding. The double pancreaticogastrostomy allowed preservation of the injured pancreatic head considering the distal pancreatic fluid outflow from the pancreatic head and required no anastomoses to the small intestine.

＜文献概要＞早期慢性膵炎の概念は,早期治療介入により病状進行の抑制が期待できる点で重要である.早期慢性膵炎の診断基準は「慢性膵炎臨床診断基準2009」で初めて定義された.その後,2011年に行われた慢性膵炎全国調査,早期慢性膵炎の前方視的コホート・スタディなどの知見の集積を受け,2019年に慢性膵炎臨床診断基準が改訂され,早期慢性膵炎の診断基準も改訂された.2019年の早期慢性膵炎診断基準では,「急性膵炎の既往」が項目として追加されたこと,アルコール摂取量の基準が1日60g(純エタノール換算)に低減されたこと,などがおもな改訂点である.今後のさらなる知見の集積により,未だ不明な点が多い慢性膵炎の病態の理解が進むことを期待したい.

＜文献概要＞早期慢性膵炎の概念は,早期治療介入により病状進行の抑制が期待できる点で重要である.早期慢性膵炎の診断基準は「慢性膵炎臨床診断基準2009」で初めて定義された.その後,2011年に行われた慢性膵炎全国調査,早期慢性膵炎の前方視的コホート・スタディなどの知見の集積を受け,2019年に慢性膵炎臨床診断基準が改訂され,早期慢性膵炎の診断基準も改訂された.2019年の早期慢性膵炎診断基準では,「急性膵炎の既往」が項目として追加されたこと,アルコール摂取量の基準が1日60g(純エタノール換算)に低減されたこと,などがおもな改訂点である.今後のさらなる知見の集積により,未だ不明な点が多い慢性膵炎の病態の理解が進むことを期待したい.

BACKGROUND: Capicua transcriptional repressor (CIC) -rearranged sarcoma is characterized by small round cells, histologically similar to Ewing sarcoma. However, CIC-rearranged sarcoma has different clinical, histological, and immunohistochemical features from Ewing sarcoma. It is important to differentiate between these tumors. CASE PRESENTATION: The patient is a 44-year-old man with a duodenal tumor diagnosed in another hospital who presented with a history of melena. Laboratory studies showed anemia with a serum hemoglobin of 6.0 g/dL. He was hospitalized and gastrointestinal bleeding was controlled successfully with endoscopy. However, he suffered from appetite loss and vomiting and progression of anemia a few weeks after presentation. Upper gastrointestinal endoscopy showed a circumferential soft tumor in the second portion of the duodenum and the endoscope could not pass distally. Computed tomography scan showed a greater than 10 cm tumor in the duodenum, with compression of the inferior vena cava and infiltrating the ascending colon. A definitive pathologic diagnosis could not be established despite four biopsies from the tumor edge. Due to gastrointestinal obstruction and progression of anemia, a pylorus-preserving pancreaticoduodenectomy with partial resection of the inferior vena cava and right hemicolectomy was performed as a complete tumor resection. The tumor was diagnosed as a CIC-rearranged sarcoma, but 2 months postoperatively local recurrence and distant metastases to the liver and lung were found. The patient died 3 months after surgery. CONCLUSIONS: Although the only definitive treatment for CIC-rearranged sarcoma is surgical resection, the CIC-rearranged sarcoma is highly malignant with a poor prognosis even after radical resection. More research is needed to establish optimal treatment strategies.

BACKGROUND: Thymomas are typically slow-growing tumors and AB type thymomas are considered no/low risk tumors with a better prognosis. Extra-thoracic metastases are extremely rare. To the best of our knowledge, no patient with an isolated splenic metastasis from a thymoma has been reported. We report a patient who underwent laparoscopic splenectomy for a slow-growing, isolated splenic metastasis, eight years after thymectomy. CASE PRESENTATION: The patient is a 78-year-old man. Eight years previously, the patient underwent extended thymectomy and postoperative radiation therapy for a thymoma. Five years after thymectomy, a nodule appeared in the spleen, and the lesion enlarged gradually for three years thereafter. The patient was referred for further examination and treatment. Computed tomography scan showed a sharply circumscribed 50 mm tumor slightly hypodense and heterogeneous lesion in the spleen. On T2-weighted images on Magnetic Resonance Imaging, the tumor had high intensity, equivalent to or slightly lower than that on T1-weighted images, and no decrease on diffusion-weighted images. The tumor was multinodular and showed a low-signal spoke-wheel sign in the margin, enhanced gradually in the dynamic study. Positron emission tomography-CT scan, showed relatively low accumulation. Surgical resection was undertaken, and pathological examination showed metastatic thymoma. The patient is without recurrence and has no other symptoms three years after splenectomy. CONCLUSIONS: This is the first report of an isolated splenic metastasis from a thymoma. Further cases are needed to standardize this surgery for such lesions.