Retrospective Study
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World J Gastroenterol. Dec 21, 2014; 20(47): 17949-17954
Published online Dec 21, 2014. doi: 10.3748/wjg.v20.i47.17949
Clinicopathological features of small nonfunctioning pancreatic neuroendocrine tumors
Mariko Furukori, Koji Imai, Hidenori Karasaki, Kenji Watanabe, Kensuke Oikawa, Naoyuki Miyokawa, Masahiko Taniguchi, Hiroyuki Furukawa
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
Hidenori Karasaki, Department of Surgery, Sapporo Higashi Tokushukai Hospital, Sapporo city, Hokkaido 065-0033, Japan
Kensuke Oikawa, Naoyuki Miyokawa, Department of Surgical Pathology, Asahikawa Medical College Hospital, Hokkaido 078-8510, Japan
Author contributions: Furukori M designed the study and wrote the manuscript; Furukori M, Imai K, Watanabe K and Karasaki H collected the patients’ clinical data; Oikawa K and Miyokawa N performed the pathological examination; Taniguchi M and Furukawa H were involved in editing the manuscript.
Correspondence to: Masahiko Taniguchi, MD, PhD, Division of Gastroenterological and General Surgery, Department of Surgery, Asahikawa Medical University, Midorigaoka-higashi 2-1-1-1, Asahikawa city, Hokkaido 078-8510, Japan. tonny@isis.ocn.ne.jp
Telephone: +81-116-682503 Fax: +81-116-682193
Received: January 25, 2014
Revised: May 9, 2014
Accepted: July 29, 2014
Published online: December 21, 2014
Abstract

AIM: 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.

CONCLUSION: 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.

Keywords: Pancreatic neuroendocrine tumor, Pancreatic neuroendocrine carcinoma, Nonfunctioning, Lymphadenectomy, Treatment

Core tip: We present our experience in studying the clinicopathological features of small nonfunctioning pancreatic neuroendocrine tumors (NE-pNETs). In the present study, six of the 7 patients with sporadic NF-pNETs, excluding the patient with NEC, had small tumors that were less than 10 mm. These small tumors showed no sign of malignancy or lymph node metastasis. Additionally, these cases did not have recurrence, including lymph node and distant metastasis, for more than 10 years after surgery. These findings suggest that small NF-pNETs tend to have less malignant potential and no lymph nodes metastasis. Lymphadenectomy may be omitted in the future for small NF-pNETs after further investigation.