title: Clinicopathological features of small nonfunctioning pancreatic neuroendocrine tumors.
abstract: OBJECTIVE
  To present our experiences in studying the clinicopathological features of small nonfunctioning pancreatic neuroendocrine tumors (NF-pNETs).
  
  
  METHODS
  The subjects included 9 patients with NF-pNETs who underwent pancreatectomy between April 1996 and September 2012. The surgical procedure, histopathological findings, and prognosis were assessed.
  
  
  RESULTS
  All tumors were incidentally detected by computed tomography. The median diameter was 10 mm (5-32 mm). One patient was diagnosed with von Hippel-Lindau disease, and the others were sporadic cases. For the histopathological findings, 7 patients were G1; 1 patient was G2; and 1 patient, whose tumor was 22 mm, had neuroendocrine carcinoma (NEC). One patient who had a tumor that was 32 mm had direct invasion to a regional lymph node and 1 patient with NEC, had regional lymph node metastases. Six of the 7 patients with sporadic NF-pNETs, excluding the patient with NEC, had tumors that were smaller than 10 mm. Tumors smaller than 10 mm showed no malignancy and lacked lymph node metastasis.
  
  
  CONCLUSIONS
  Sporadic NF-pNETs smaller than 10 mm tend to have less malignant potential. These findings suggest that lymphadenectomy may be omitted for small NF-pNETs after further investigation.
authors.affiliation: Mariko Furukori, Koji Imai, Kenji Watanabe, Masahiko Taniguchi, Hiroyuki Furukawa, Division of Gastroenterological and General Surgery, Department of Surgery, Asahikawa Medical University, Hokkaido 078-8510, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Furukori
authors.affiliation: Mariko Furukori, Koji Imai, Kenji Watanabe, Masahiko Taniguchi, Hiroyuki Furukawa, Division of Gastroenterological and General Surgery, Department of Surgery, Asahikawa Medical University, Hokkaido 078-8510, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Imai
authors.affiliation: Mariko Furukori, Koji Imai, Kenji Watanabe, Masahiko Taniguchi, Hiroyuki Furukawa, Division of Gastroenterological and General Surgery, Department of Surgery, Asahikawa Medical University, Hokkaido 078-8510, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Karasaki
authors.affiliation: Mariko Furukori, Koji Imai, Kenji Watanabe, Masahiko Taniguchi, Hiroyuki Furukawa, Division of Gastroenterological and General Surgery, Department of Surgery, Asahikawa Medical University, Hokkaido 078-8510, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Mariko Furukori, Koji Imai, Kenji Watanabe, Masahiko Taniguchi, Hiroyuki Furukawa, Division of Gastroenterological and General Surgery, Department of Surgery, Asahikawa Medical University, Hokkaido 078-8510, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Oikawa
authors.affiliation: Mariko Furukori, Koji Imai, Kenji Watanabe, Masahiko Taniguchi, Hiroyuki Furukawa, Division of Gastroenterological and General Surgery, Department of Surgery, Asahikawa Medical University, Hokkaido 078-8510, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Miyokawa
authors.affiliation: Mariko Furukori, Koji Imai, Kenji Watanabe, Masahiko Taniguchi, Hiroyuki Furukawa, Division of Gastroenterological and General Surgery, Department of Surgery, Asahikawa Medical University, Hokkaido 078-8510, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Taniguchi
authors.affiliation: Mariko Furukori, Koji Imai, Kenji Watanabe, Masahiko Taniguchi, Hiroyuki Furukawa, Division of Gastroenterological and General Surgery, Department of Surgery, Asahikawa Medical University, Hokkaido 078-8510, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Furukawa
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood; D005260:Female; D006801:Humans; D033162:Incidental Findings; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D008940:Mitotic Index; D009367:Neoplasm Staging; D018358:Neuroendocrine Tumors / Q000097:blood / Q000000981:diagnostic imaging / Q000556:secondary* / Q000601:surgery; D010180:Pancreatectomy; D010190:Pancreatic Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D010751:Phosphopyruvate Hydratase / Q000097:blood; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D014408:Biomarkers, Tumor; D010751:Phosphopyruvate Hydratase
keywords: Lymphadenectomy; Nonfunctioning; Pancreatic neuroendocrine carcinoma; Pancreatic neuroendocrine tumor; Treatment