Case Report
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World J Gastroenterol. May 28, 2013; 19(20): 3161-3164
Published online May 28, 2013. doi: 10.3748/wjg.v19.i20.3161
Intraductal papillary neoplasm of the bile duct accompanying biliary mixed adenoneuroendocrine carcinoma
Ichiro Onishi, Hirohisa Kitagawa, Kenichi Harada, Syogo Maruzen, Seisyo Sakai, Isamu Makino, Hironori Hayashi, Hisatoshi Nakagawara, Hidehiro Tajima, Hiroyuki Takamura, Takashi Tani, Masato Kayahara, Hiroko Ikeda, Tetsuo Ohta, Yasuni Nakanuma
Ichiro Onishi, Hirohisa Kitagawa, Syogo Maruzen, Seisyo Sakai, Isamu Makino, Hironori Hayashi, Hisatoshi Nakagawara, Hidehiro Tajima, Hiroyuki Takamura, Takashi Tani, Masato Kayahara, Tetsuo Ohta, Department of Gastroenterologic Surgery, Graduate School of Medical Science, Kanazawa University, Kanazawa 920-8641, Japan
Kenichi Harada, Yasuni Nakanuma, Department of Human Pathology, Graduate School of Medical Science, Kanazawa University, Kanazawa 920-8650, Japan
Hiroko Ikeda, Pathology Division, Kanazawa University Hospital, Kanazawa 920-8650, Japan
Author contributions: Onishi I and Kitagawa H contributed equally to this work; Onishi I, Kitagawa H, Takamura H, Tani T, Kayahara M and Ohta T performed surgery; Maruzen S, Sakai S, Makino I, Hayashi H, Nakagawara H and Tajima H managed postoperative treatment; Harada K, Ikeda H and Nakanuma Y made the pathologic diagnosis; Onishi I, Kitagawa H and Harada K wrote the paper.
Correspondence to: Ichiro Onishi, MD, PhD, Department of Gastroenterologic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-8641, Japan. ionishi@kinbyou.hosp.go.jp
Telephone: +81-76-2624161 Fax: +81-76-2222758
Received: December 24, 2012
Revised: March 13, 2013
Accepted: April 3, 2013
Published online: May 28, 2013
Abstract

We present the first case of an intraductal papillary neoplasm of the bile duct (IPNB) accompanying a mixed adenoneuroendocrine carcinoma (MANEC). A 74-year-old woman presented with fever of unknown cause. Laboratory data revealed jaundice and liver injury. Contrast-enhanced computed tomography revealed a 20 mm polypoid tumor in the dilated distal bile duct, which exhibited early enhancement and papillary growth. Upper gastrointestinal endoscopy revealed mucus production from the papilla of Vater, characterized by its protruding and dilated orifice. Endoscopic ultrasonography visualized the polypoid tumor in the distal bile duct, but no invasive region was suggested by diagnostic imaging. Therefore, the initial diagnosis was IPNB. After endoscopic nasobiliary drainage, a pylorus-preserving pancreaticoduodenectomy was performed. Pathological examination of the resected bile duct revealed papillary proliferation of biliary-type cells with nuclear atypia, indicating pancreaticobiliary-type IPNB. In addition, solid portions comprised of tumor cells with characteristic salt-and-pepper nuclei were evident. Immunohistochemistry revealed expression of the neuroendocrine marker synaptophysin in this solid component, diagnosing it as a neuroendocrine tumor (NET). Furthermore, the MIB-1 proliferation index of NET was higher than that of IPNB, and microinvasion of the NET component was found, indicating neuroendocrine carcinoma (NET G3). This unique case of MANEC, comprising IPNB and NET, provides insight into the pathogenesis of biliary NET.

Keywords: Neuroendocrine tumor, Intraductal papillary neoplasm of bile duct, Intraductal papillary neoplasm of the bile duct, Bile duct

Core tip: A 74-year-old woman presented with fever and jaundice. Computed tomography revealed a polypoid tumor in the dilated distal bile duct. Pylorus-preserving pancreaticoduodenectomy was performed. Pathological examination revealed the papillary proliferation of biliary-type cells with nuclear atypia in the dilated bile duct, indicating papillary neoplasm of the bile duct. A solid portion comprised of tumor cells with characteristic salt-and-pepper nuclei was found. Immunohistochemistry revealed synaptophysin expression in the solid portion, diagnosing it as a neuroendocrine tumor (NET). This case provides insight into the pathogenesis of biliary NET.