Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Hiroki Hayakawa is active.

Publication


Featured researches published by Hiroki Hayakawa.


Journal of Gastroenterology | 2000

Triple carcinomas of the biliary tract associated with congenital choledochal dilatation and pancreaticobiliary maljunction

Kazunori Okamura; Hiroki Hayakawa; Masaya Kuze; Hiroaki Takahashi; Atsushi Kosaka; Ryuji Mizumoto; Koji Katsuta

Abstract: We report a rare case of triple carcinomas of the biliary tract associated with congenital choledochal dilatation (CCD) and pancreaticobiliary maljunction (PBM). The patient was a 58-year-old Japanese man who complained of epigastralgia. Ultrasonography and computed tomography revealed an elevated lesion inside the markedly dilated extrahepatic bile duct, thickening of the gallbladder wall, and small polypoid lesions in the gallbladder. Magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography showed CCD and PBM. With a diagnosis of carcinoma of the bile duct and cholesterol polyps in the gallbladder, pylorus-preserving pancreaticoduodenectomy was performed. The resected specimen showed two elevated lesions in the dilated bile duct, cholesterol polyps, and an area of irregular mucosa in the gallbladder. Histopathological examination showed two carcinomas in the bile duct, an adenosquamous cell carcinoma, and a moderately differentiated tubular adenocarcinoma, and a well differentiated tubular adenocarcinoma of the gallbladder. Two years and 6 months after the operation, a solitary metastatic liver tumor was detected. Left hepatic lobectomy was performed. At present, 7 months after the second operation, the patient is doing well with no signs of recurrence. Multiple carcinomas in the biliary tract associated with CCD and PBM, including the details in the present patient, were reviewed.


Surgery Today | 1999

Successful surgical treatment for implanted intraperitoneal metastases of ruptured small hepatocellular carcinoma: report of a case.

Atsushi Kosaka; Hiroki Hayakawa; Masayuki Kusagawa; Hiroaki Takahashi; Kazunori Okamura; Ryuji Mizumoto; Koji Katsuta

We report herein the case of a 53-year-old man with disseminated intraperitoneal metastases caused by the rupture of small hepatocellular carcinoma (HCC). He was admitted to our hospital in shock after suffering a trauma injury to the upper abdomen. Ultrasonography revealed a massive hemoperitoneum. At surgery, 4000 ml of blood was drained from the abdominal cavity and a ruptured tumor, 2 cm in diameter, was found in the right lobe of the liver. The tumor was resected with an adequate surgical margin and subsequent microscopic examination confirmed a diagnosis of moderately differentiated HCC without associated liver cirrhosis. The patient was readmitted 14 months later, following the development of right lower quadrant pain. Ultrasonography and computed tomography revealed extrahepatic abdominal tumors, and abdominal angiography demonstrated four intraperitoneal tumors. At surgery, four implanted metastases adhered to the greater omentum were found and resected. No other tumors were detected. Microscopically, all four tumors were confirmed as moderately differentiated hepatocellular carcinoma. Ruptured HCC may lead to implanted intraperitoneal metastasis, but rupture of small HCC is very rare. While hepatic resection is the treatment of choice for ruptured HCC, according to our review of the literature, only a few patients have survied long-term after resection of implanted metastasis.


Journal of Gastroenterology | 1997

Primary adenosquamous carcinoma of liver resected by right trisegmentectomy: Report of a case and review of the literature

Hiroaki Takahashi; Hiroki Hayakawa; Minoru Tanaka; Kazunori Okamura; Atsushi Kosaka; Ryuji Mizumoto; Koji Katsuta; Ryuichi Yatani

A case of primary adenosquamous carcinoma of the liver in a patient with an elevated level of serum squamous cell carcinoma-related antigen is reported. A 68-year-old man was admitted to our hospital with a 10-day history of fever and jaundice. From the results of laboratory and imaging studies before surgery, a diagnosis of cholangiocellular carcinoma was made, and the patient underwent right trisegmentectomy with regional lymph node dissection. Histopathological examination of the resected specimen revealed adenocarcinoma, squamous cell carcinoma, and a transitional area containing both types of cancer cells. The number of argyrophilic nucleolar organizer regions and the labeling index of proliferating cell nuclear antigen were markedly elevated and the deoxyribonucleic acid ploidy pattern was aneuploid in the squamous component. The patient died due to liver metastases 3 months after the operation. We reviewed the 31 cases of adenosquamous carcinoma of the liver reported in the Japanese and English language literature, including the present case.


Surgery Today | 1999

Solid cystic tumor of the pancreas in elderly men: report of a case.

Hiroaki Takahashi; Kenji Hashimoto; Hiroki Hayakawa; Masayuki Kusakawa; Kazunori Okamura; Atsushi Kosaka; Ryuji Mizumoto; Koji Katsuta

Solid cystic tumor of the pancreas is a primary pancreatic neoplasm of unknown etiology that most commonly occurs in young women and ordinarily contains hemorrhagic tissue. We report herein the unusual case of a 75-year-old man found to have a solid cystic tumor in the body and tail of the pancreas, who is the oldest such male patient to be documented in Japan. The results of laboratory data and imaging studies indicated that the patient had a nonfunctioning islet tumor or solid cystic tumor of the pancreas, and distal pancreatectomy with splenectomy was performed. The diagnosis of solid cystic tumor was confirmed based on macroscopic and histological findings of the resected pancreatic tumor. The patient is currently in good health, without any signs of tumor recurrence 1 year, and 4 months after his operation. A total of 181 cases of solid cystic tumors, of the pancreas reported in the Japanese literature, including our case, were reviewed to evaluate the clinical differences between patients aged 50 years or over and those younger than 50 years.


Surgery Today | 1998

Arteriovenous Malformation of the Rectum: Report of a Case

Hiroki Hayakawa; Masayuki Kusagawa; Hiroaki Takahashi; Kazunori Okamura; Atsushi Kosaka; Ryuji Mizumoto; Koji Katsura

We report herein the case of a 38-year-old man found to have a rectal arteriovenous malformation (AVM). The patient was admitted to our hospital for investigation of fresh anal bleeding and general malaise. Barium-enema examination showed a slightly elevated lesion in the rectum, and a selective superior rectal angiogram subsequently revealed an AVM in the peripheral region of the superior rectal artery, which was presumed to be the cause of the anal bleeding. Colonoscopic examination disclosed a submucosal tumor-like lesion in the left posterior wall of the rectum, 3cm above the anal verge. After marking the boundaries by clipping, transanal resection of the lesion was performed. Histological examination revealed an irregularly expanded arteriovenous aggregation in the submucosal layer. The patient had a favorable postoperative course, and no residual AVM was seen on a postoperative selective inferior mesenteric arteriogram. There have been no signs of recurrence in the 2 years since his operation.


Surgery Today | 1998

Giant leiomyosarcoma of the remnant stomach: Report of a case

Kazunori Okamura; Hiroki Hayakawa; Masayuki Kusakawa; Hiroaki Takahashi; Atsushi Kosaka; Ryuji Mizumoto; Koji Katsuta

We describe herein the case of a 73-year-old woman who developed a giant leiomyosarcoma in the remnant stomach 4 years after undergoing a distal gastrectomy for gastric carcinoma. Abdominal ultrasonography and computed tomography revealed a huge tumor, 22 cm in maximum diameter, in the left hypochondrial region. Selective abdominal angiography showed a hypervascular tumor fed by the branches of the splenic artery and left inferior phrenic artery. The tumor arose from the posterior wall of the remnant stomach, and demonstrated marked extragastric growth and direct invasion of the pancreas, transverse colon, and diaphragm on the left side. Total resection of the remnant stomach with en bloc resection of these adjacent organs was subsequently carried out. We reviewed the Japanese literature on this extremely rare tumor and evaluated its clinical profile. In comparison with leiomyosarcoma of the unresected stomach, that of the remnant stomach more frequently showed endogastric-type growth and was accompanied by ulceration of the gastric mucosa. The prognosis of patients with leiomyosarcoma of the remnant stomach appears to be gratly affected by the presence of liver metastases and the tumor diameter, similar to that of patients with leiomyosarcoma of the unresected stomach.


International Journal of Pancreatology | 1998

Treatment of pancreas head carcinoma in a 91-yr-old man. Report of a case successfully treated with pylorus-preserving pancreatoduodenectomy.

Kazunori Okamura; Hiroki Hayakawa; Masayuki Kusagawa; Hiroaki Takahashi; Atsushi Kosaka; Koji Katsuta; Ryuji Mizumoto

SummaryThe case of a 91-yr-old man who had a tumor of the pancreas head successfully resected is reported. He was admitted to our hospital because of obstructive jaundice, and then percutaneous transhepatic biliary drainage (PTBD) was performed. Cholangiography via PTBD tube showed marked stenosis of the bile duct in the head of the pancreas. Endoscopic retrograde pancreatography (ERP) showed obstruction of the main pancreatic duct in the head of the pancreas, and carcinoma in the head of the pancreas was diagnosed. Abdominal angiography showed stenosis of the celiac trunk caused by compression from the median arcuate ligament, but no tumor stain or encasement in the pancreas was detected. Because the patient had lived an extremely healthy life and had no serious concurrent disease before admission, laparotomy was performed. The tumor in the head of the pancreas was about 2 cm in diameter and restricted inside the pancreas. Pylorus-preserving pancreatoduodenectomy (PpPD) with regional lymph node dissection was performed. The tumor was 1.5 cm in its maximal diameter, and histopathologically was diagnosed as an invasive ductal carcinoma of the pancreas with moderately differentiated tubular adenocarcinoma. The patient had an uneventful postoperative course and now, 3 yr after surgery, he is doing very well and leading a normal daily life.


Nihon Rinsho Geka Gakkai Zasshi (journal of Japan Surgical Association) | 2001

A CASE OF NECROTIZING ENTEROCOLITIS WITH HEPATIC PORTAL VENOUS GAS AND PNEUMATOSIS CYSTOIDES INTESTINALIS

Takashi Tomita; Hiroaki Takahashi; Hiroki Hayakawa


Nihon Rinsho Geka Gakkai Zasshi (journal of Japan Surgical Association) | 1998

A DISTAL GASTRECTOMY FOR CARCINOMA DEVELOPED IN THE RECONSTRUCTED GASTRIC TUBE 13 YEARS AFTER ESOPHAGECTOMY FOR THORACIC ESOPHAGEAL CANCER -A CASE REPORT-

Hiroki Hayakawa; Masayuki Kusagawa; Hiroaki Takahashi; Kazunori Okamura; Atsushi Kosaka; Kouji Katsuta


Nihon Rinsho Geka Gakkai Zasshi (journal of Japan Surgical Association) | 2002

A CASE OF SARCOMATOID CARCINOMA OF THE SIGMOID COLON

Hiroaki Takahashi; Hiroki Hayakawa; Takashi Tomita

Collaboration


Dive into the Hiroki Hayakawa's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Masayuki Kusagawa

Memorial Hospital of South Bend

View shared research outputs
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge