Koichiro Ozawa

Perineural invasion in pancreatic cancer

Introduction Perineural invasion is regarded as a factor associated with local recurrence of pancreatic cancer. Aim To examine perineural invasion of pancreatic cancer pathologically and clinically. Methodology In 24 cases of surgically resected pancreatic cancer, correlations among the degree of perineural invasion, differentiation, interstitial connective tissue, lymph node metastasis, and survival rate were examined. Consecutive 5-&mgr;m serial sections (n = 1072) were made in six cases that showed characteristic mode of perineural invasion. Results Perineural invasion was observed in 17 cases (70.8%; ne0–7; ne1–6; ne2–9; and ne3–2 cases). Perineural invasion was absent in three of five cases of papillary carcinoma, but was observed in 12 of 14 cases of moderately differentiated carcinoma. The survival rate for ne0 was better than that of the other groups, with the 3-year survival rate being 57.1%. Perineural cancer glands had developed discontinuously in two cases. Conclusions Perineural invasion is an important prognostic factor in pancreatic cancer, increasing as the cancer becomes undifferentiated. Even if there are no cancer cells at the margin of the pancreas at the time of surgery, the cancer cells may spread further to the noncancerous pancreas or retroperitoneum. Sufficient dissection of the neural plexus or intraoperative radiation may be required.

Minute invasive ductal carcinoma of the residual pancreas after distal pancreatectomy for intraductal papillary-mucinous tumor.

SummaryOur report describes a 66-yr-old man who underwent surgical resection of the pancreas twice within a period of 3 yr for primary and recurrent intraductal papillary mucinous tumors (IPMTs). During the second operation, a minute invasive ductal carcinoma (IDC) was accidentally discovered in the resected specimen of the residual pancreas. The similarity and continuity between this IDC and recurrent IPMT were not recognized histologically. A solid tumor was found in the hepatoduodenal ligament 3 mo after the second operation. We performed a third operation, performing laparotomy and intra-operative radiotherapy, but could not extirpate the tumor. A biopsy specimen obtained from the tumor during this third operation revealed adenocarcinoma, and the patient later died because of tumor progression. We immunohistochemically analyzed the expression of HER-2/neu, Smad4, p16, p21, p53, mucin immunophenotypes and the Ki-67 labeling index in this series of pancreatic-duct neoplasias. Overexpression of HER-2/neu and loss of Smad4 were detected in the minute IDC, which was very different from the immunohistochemical features of both the primary and recurrent IPMTs. The IDC also showed a MUC1-positive/MUC2-negative phenotype. Therefore, we suggest that de novo IDC may occur in IPMT patients, especially those with multiple tumor recurrence. The present case may be helpful in understanding the pathogenesis of pancreatic duct lesions.

Successful resection of a liver metastasis from gastric leiomyoblastoma: report of a case.

A 20-year-old woman was referred to our hospital for detailed investigation of a gastric submucosal tumor. A leiomyoma was preoperatively diagnosed and laparoscopic-assisted enucleation was performed. The resected tumor was 4 × 3 × 1.5 cm in size and postoperative histological examination identified it as a gastric leiomyoblastoma. Therefore, a secondary resection in the form of a distal gastrectomy was carried out. No tumor cells were found in the gastric specimen or in the lymph nodes; however, 5 months after the operation, an abdominal computed tomography scan revealed a recurrence in the liver, and she was readmitted for further examinations. The lesion was diagnosed as a single liver metastasis from the gastric leiomyoblastoma and successfully resected. The histopathological findings of the liver tumor resembled those of the primary gastric tumor. Her postoperative course was uneventful and she has been well, without any evidence of recurrence, to date. Only 12 other cases of leiomyoblastoma of the stomach with liver metastasis have been reported in Japan, all of which were associated with a very poor prognosis. Therefore, patients with this unusual disease entity should be carefully followed up after resection of the primary tumor.

Tu1575 Conservative Treatment and Interval Appendectomy for Acute Appendicitis

BACKGROUND Conservative treatment for acute appendicitis (AA) is gradually being adopted as valuable therapeutic choice. Interval appendectomy (IA) after conservative treatment is controversial. OBJECTIVE To clarify the success and recurrence rate of conservative treatment for acute appendicitis, and necessity of IA Patients and Methods We reviewed 503 patients with AA between 2006 and 2013. RESULTS In 503 patients, of which 122 patient undergone emergency appendectomy within 3 days after admission, remaining 381 patients underwent conservative treatment. In 381 patients taken conservative treatment, the success rate of conservative treatment was 98%. Nine patients (2%) were required appendectomy because of progressive disease despite of conservative treatment. After conservative treatment 95 patients (27%) were diagnosed as a recurrent AA at median follow-up 18 months. The predictor for recurrence after conservative treatment was the only following multiple episodes of AA (p=0.002, HR 2.1, 95%CI [1.56-41.1]). The abscess formation and appendicolith did not predict the disease recurrence. At the recurrent AA, 37 of 95 (39%) patients underwent appendectomy including IA. The morbidity of appendectomy for recurrent disease was 5%. Especially the morbidity of IA for recurrent disease was 0%. CONCLUSIONS The success rate of conservative treatment was very high and the risk of recurrence after conservative treatment was 27%. The morbidity of appendectomy for recurrent disease was low (5%). The conservative treatment may be an effective alternative to emergency appendectomy. The routine IA is probably not warranted following successful management of AA, but IA should be required to patients with multiple episodes of AA. Morbidity rate of appendectomy by timing of operation