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Review
. 2022 Apr 1;51(4):338-344.
doi: 10.1097/MPA.0000000000002029. Epub 2022 Jun 14.

Clinical Features of Pancreatic Neuroendocrine Microadenoma: A Single-Center Experience and Literature Review

Yuki Okawa  1 , Takahiro Tsuchikawa  1 , Kanako C Hatanaka  2 , Aya Matsui  1 , Kimitaka Tanaka  1 , Yoshitsugu Nakanishi  1 , Toshimichi Asano  1 , Takehiro Noji  1 , Toru Nakamura  1 , Tomoko Mitsuhashi  3 , Keisuke Okamura  1 , Yutaka Hatanaka  4 , Satoshi Hirano  1
Affiliations
Review

Clinical Features of Pancreatic Neuroendocrine Microadenoma: A Single-Center Experience and Literature Review

Yuki Okawa et al. Pancreas. .

Abstract

Objectives: Pancreatic neuroendocrine microadenoma (NEMA) is a nonfunctioning neuroendocrine tumor of less than 5 mm. Most studies of NEMA were based on autopsies, and few reports have revealed the clinical frequency of NEMA. We investigated the clinicopathological features of NEMA.

Methods: The pathological results of the pancreatic resection specimens of patients, older than 18 years, who underwent pancreatic resection at Hokkaido University Hospital between April 2008 and December 2020 were retrospectively reviewed. The NEMAs were re-examined in detail and examined by immunohistochemical staining.

Results: Among 850 patients enrolled in this study, 24 NEMAs were identified in 12 patients (1.4%). Of the 12 patients, 2 patients had multiple endocrine neoplasia type 1, and the others had no hereditary disease, including 2 patients with multiple NEMAs. A difference in the number of NEMA was observed between patients with multiple endocrine neoplasia type 1 and sporadic NEMA. Intratumoral Ki-67 heterogeneity was correlated with the Ki-67 index. One grade 2 NEMA (Ki-67 index, 4.6%) was detected, but ATRX and DAXX labeling showed intact nuclear protein expression.

Conclusions: Multiple sporadic NEMAs and grade 2 NEMAs were observed, suggesting that NEMA may have malignant potential. Thus, NEMAs should be carefully monitored for lymph node metastasis and postoperative recurrence.

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Conflict of interest statement

The authors declare no conflict of interest.

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Supplementary concepts