日本消化器病学会 アーカイブシステム

セッション情報 The 4th International Forum

Short Oral Presentations（Pancreaticobiliary disorders 2）
タイトル IF-SOP-16：

Is the WHO 2010 classification sufficient to clearly characterize pancreatic neuroendocrine carcinoma?
演者 Hijioka　Susumu（Department of Gastroenterology, Aichi Cancer Center Hospital, Japan）
共同演者 Mizuno　Nobumasa（Department of Gastroenterology, Aichi Cancer Center Hospital, Japan）, Hara　Kazuo（Department of Gastroenterology, Aichi Cancer Center Hospital, Japan）, Imaoka　Hiroshi（Department of Gastroenterology, Aichi Cancer Center Hospital, Japan）, Hosoda　Waki（Department of Pathology and Molecular Diagnostics, Aichi Cancer Center Hospital, Japan）, Yamao　Kenji（Department of Gastroenterology, Aichi Cancer Center Hospital, Japan）
抄録 Background：The WHO 2000 classification of pancreatic neuroendocrine tumors（pNET）addressed morphological differentiation as the first criterion；however, the 2010 classification is based on histological grading. Neuroendocrine tumors are classified as NET G1, NET G2, and neuroendocrine carcinoma（NEC）according to mitosis and/or the Ki67 labeling index（Ki-67）. G1/G2 NETs and NEC are well- and basically poorly differentiated, respectively. However, some pathologically well-differentiated tumors with Ki-67 ＞20%（NET G3）are now categorized as NEC.
Methods：We retrospectively compared imaging findings, morphological differentiation, KRAS mutations, treatment and the prognoses of nine patients diagnosed with NECs between 2001 and 2013 according to the 2010 classification.
Results：The mean tumor size was 35 mm. One and eight patients had Stages 3b and 4, and seven and two had CT vascularity and hypo/hypervascularity, respectively, based on the ENETS classification. Three and six patients, respectively, had well/poorly differentiated tumors, idicating that NEC included 33% NET G3.
The average rates of Ki67 and KRAS mutation positivity were 44% and 62.5%, respectively, and mean survival time（MST）was 320 days. A clinicopathological comparison of NET G3 with NEC showed CT vascularity, KRAS mutations, average Ki67 and MST in 67% and 0%, 0% and 83%, 40% and 63.5% of the patients, and 320 and 206 days, respectively.
Conclusions：A significant proportion of NET G3 was classified as NEC based on the 2010 classifications, but NEC and NET G3 differed clinicopathologically. These features should be reconsidered, and a change in the classification is warranted in the near future.

Key words：NET, NEC, WHO classification
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