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Dive into the research topics where Naoki Maehara is active.

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Featured researches published by Naoki Maehara.


Surgery Today | 2006

Segmentectomy for reactive lymphoid hyperplasia of the liver : Report of a case

Naoki Maehara; Kazuo Chijiiwa; Ichiro Makino; Jiro Ohuchida; Masahiro Kai; Kazuhiro Kondo; Sayaka Moriguchi; Kousuke Marutsuka; Yujiro Asada

We report a case of reactive lymphoid hyperplasia (RLH) of the liver in a 72-year-old woman without any symptoms. To our knowledge, only 11 other cases of this disease have ever been reported. The lesion was found incidentally during a medical examination, as a hypoechoic mass in segment 3 of the liver on ultrasonography. The findings of computed tomography, magnetic resonance imaging, and angiography suggested a malignancy. Frozen section diagnosis of an intraoperative needle biopsy suggested malignant lymphoma, so we performed lateral segmentectomy of the liver. Macroscopically, the tumor was well defined, white, and firm. Microscopically, there was polymorphous lymphoplasmacytic infiltration, with various-sized and -shaped lymphoid follicles. Lymphocytic infiltration was also observed in the portal tracts around the nodular lesion. Immunohistochemical study revealed polyclonality, confirming a pathological diagnosis of RLH of the liver. We discuss the clinicopathologic characteristics of this unusual disease.


World Journal of Surgery | 2007

Sex Difference in Survival of Patients Treated by Surgical Resection for Esophageal Cancer

Hideki Hidaka; Shinya Nakashima; Shuichiro Uchiyama; Naoki Maehara; Kazuo Chijiiwa

AbstractBackgroundSquamous cell carcinoma accounts for most of the esophageal cancers in Japan and is often related to excessive smoking and drinking. Although esophageal cancer occurs far more frequently in men than in women, it is not certain whether there are sex-specific differences in morbidity and mortality after surgical resection of the esophagus. We conducted a study to determine the influence of sex on the short- and long-term results of surgical resection in patients with esophageal cancer.MethodsThere were 295 patients with a newly diagnosed primary malignant neoplasm of the esophagus treated at our University hospital between January 1978 and December 2005. There were 185 patients (166 men, 19 women; age range 39–86 years) who underwent surgical resection for primary esophageal malignant neoplasms. Survival rates were calculated according to the Kaplan-Meier method and tested with the log-rank test. Cox proportional hazards model was used to assess independent predictors of survival. ResultsThe cumulative amount of alcohol consumed and number of cigarettes smoked were significantly higher in men than in women. Postoperative complications occurred in 101 men (60.8%) and 9 women (47.4%), but significant sex differences in postoperative morbidity and mortality were not observed. Overall survival was significantly better for women than for men.Conclusion Postoperative morbidity and mortality do not appear to differ between men and women with esophageal cancer treated by surgical resection. Long-term survival after surgical resection of the esophagus appears to be significantly better for women than for men.


International Journal of Clinical Oncology | 2007

Synchronous adenocarcinoma and gastrointestinal stromal tumors of the stomach treated laparoscopically

Shuichiro Uchiyama; Motoaki Nagano; Nobuyasu Takahashi; Hideki Hidaka; Hiromitsu Matsuda; Koki Nagaike; Naoki Maehara; Kazuo Chijiiwa

Gastric adenocarcinomas account for approximately 95% of primary gastric tumors, and gastrointestinal stromal tumor (GIST) is the most common gastrointestinal mesenchymal tumor, accounting for 1%–3% of primary gastric tumors. However, the synchronous occurrence of GIST and gastric epithelial tumor is rare. We herein report a case of synchronous occurrence of gastric adenocarcinoma and two GISTs of the stomach. All lesions were resected laparoscopically. We discuss this case and review the literature.


Asian Journal of Endoscopic Surgery | 2015

Laparoscopic anterior pelvic exenteration for locoregionally advanced rectal cancer directly invading the urinary bladder: A case report of low anterior resection with en bloc cystectomy for sphincter preservation

Hidenobu Ishizaki; Shinya Nakashima; Takeomi Hamada; Takahiro Nishida; Naoki Maehara; Takuto Ikeda; Hiromasa Tsukino; Shoichiro Mukai; Toshiyuki Kamoto; Kazuhiro Kondo

Laparoscopic multi‐visceral resection in patients with T4 colorectal cancer remains controversial. A 73‐year‐old man was admitted to the hospital for rectosigmoid cancer directly invading the urinary bladder trigone without distant metastasis. We successfully performed complete resection by laparoscopic anterior pelvic exenteration while preserving the anus. After laparoscopic mobilization of the rectum, urinary bladder, and prostate, the urethra and urethral catheter were dissected to reveal the lower rectum. By pulling the urethral catheter toward the head, the prostate was excised retrogradely from the lower rectum anterior wall. The lower rectum was resected and anastomosed by the double stapling technique with a safe distal margin from the tumor. Pathological findings of the resected specimen indicated no residual tumor in the surgical margin. There was no evidence of recurrence 34 months after surgery. En bloc, R0, laparoscopic anterior pelvic exenteration for T4 rectal cancer is feasible. However, further studies with long‐term follow‐up are required to resolve oncological outcomes.


Journal of Hepato-biliary-pancreatic Surgery | 2005

Risk factors for early death after liver resection in patients with solitary hepatocellular carcinoma

Kazuhiro Kondo; Kazuo Chijiiwa; Ichiro Makino; Masahiro Kai; Naoki Maehara; Jiro Ohuchida; Seiji Naganuma


Hepato-gastroenterology | 2007

Comparison of seven prognostic staging systems in patients who undergo hepatectomy for hepatocellular carcinoma.

Kazuhiro Kondo; Kazuo Chijiiwa; Motoaki Nagano; Masahide Hiyoshi; Masahiro Kai; Naoki Maehara; Jiro Ohuchida; Hiroyuki Nakao; Yoshiaki Ohkuwa


Surgical Laparoscopy Endoscopy & Percutaneous Techniques | 2007

Internal herniation through the mesenteric opening after laparoscopy-assisted right colectomy: report of a case.

Sei-ichiro Jimi; Tada-Aki Eto; Hideki Hidaka; Naoki Maehara; Kotaro Matsumoto; Kazuo Chijiiwa


Hepato-gastroenterology | 2008

Surgical treatment for gastric GIST with special reference to liver metastases.

Naoki Maehara; Kazuo Chijiiwa; Tada-Aki Eto; Mayumi Funagayama; Shuichiro Uchiyama; Shinya Nakashima; Hideki Hidaka


Hepato-gastroenterology | 2008

Comparative effect of lymph node metastasis classified by the anatomical site or by the number of nodes involved on prognosis of patients with gastric cancer.

Hideki Hidaka; Tada-Aki Eto; Naoki Maehara; Sei-ichiro Jimi; Kazuo Chijiiwa


Environmental Health and Preventive Medicine | 2014

The genotype of the transporter associated with antigen processing gene affects susceptibility to colorectal cancer in Japanese

Takenori Yamauchi; Shouhei Takeuchi; Naoki Maehara; Yoshiki Kuroda

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