title: Two cases of resectable pancreatic cancer diagnosed by open surgical biopsy after endoscopic ultrasound fine-needle aspiration failed to yield diagnosis: case reports.
abstract: BACKGROUND
  Tumor biopsy for histological diagnosis is required preoperatively and before initiating chemotherapy or radiation therapy for patients with pancreatic cancer (Cancer of the Pancreas: Clinical Practice Guidelines, European Society for Medical Oncology). Endoscopic ultrasound fine-needle aspiration (EUS-FNA) is widely applied to obtain tissue samples for histological examination. However, in some cases, EUS-FNA cannot be performed safely or tissue samples are insufficient to establish a definitive diagnosis. We present two cases of pancreatic cancer diagnosed by open surgical biopsy after EUS-FNA failed to yield a diagnosis.
  
  
  METHODS
  Case 1 was a 50-year-old man. Computed tomography showed a hypovascular lesion in the uncus of the pancreas. Although EUS-FNA was conducted twice, we could not collect enough quantity of tissue samples to establish a definitive diagnosis. Open surgical biopsy revealed adenocarcinoma, and the patient underwent preoperative chemoradiation therapy followed by curative operation. Case 2 was a 68-year-old man. Computed tomography showed a hypovascular tumor in the uncus of the pancreas. EUS revealed a 14-mm hypoechoic lesion, but we could not perform EUS-FNA because the superior mesenteric vein was located in the puncture line. Open surgical biopsy revealed adenocarcinoma, and the patient underwent preoperative chemoradiation therapy followed by pancreaticoduodenectomy.
  
  
  CONCLUSIONS
  EUS-FNA is the first choice in the diagnostic modalities of pancreatic neoplasm, but open surgical biopsy is an effective diagnostic method if EUS-FNA is unsuccessful.
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka E-2, Suita, Osaka, 565-0871, Japan.
authors.forename: Reishi
authors.initials: R
authors.lastname: Toshiyama
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka E-2, Suita, Osaka, 565-0871, Japan.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Noda
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka E-2, Suita, Osaka, 565-0871, Japan. heguchi@gesurg.med.osaka-u.ac.jp.
authors.forename: Hidetoshi
authors.identifier: http://orcid.org/0000-0002-3232-6318
authors.initials: H
authors.lastname: Eguchi
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka E-2, Suita, Osaka, 565-0871, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Iwagami
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka E-2, Suita, Osaka, 565-0871, Japan.
authors.forename: Daisaku
authors.initials: D
authors.lastname: Yamada
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka E-2, Suita, Osaka, 565-0871, Japan.
authors.forename: Tadafumi
authors.initials: T
authors.lastname: Asaoka
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka E-2, Suita, Osaka, 565-0871, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Wada
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka E-2, Suita, Osaka, 565-0871, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Kawamoto
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka E-2, Suita, Osaka, 565-0871, Japan.
authors.forename: Kunihito
authors.initials: K
authors.lastname: Gotoh
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka E-2, Suita, Osaka, 565-0871, Japan.|Department of Surgery, Kansai Rosai Hospital, Hyogo, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takeda
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka E-2, Suita, Osaka, 565-0871, Japan.|Department of Surgery, Osaka Police Hospital, Osaka, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tanemura
authors.affiliation: Department of Pathology, Graduate School of Medicine, Osaka University, Osaka, Japan.
authors.forename: Eiichi
authors.initials: E
authors.lastname: Morii
authors.affiliation: Department of Health Sciences, Graduate School of Medicine, Osaka University, Osaka, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Umeshita
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka E-2, Suita, Osaka, 565-0871, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Mori
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka E-2, Suita, Osaka, 565-0871, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Doki
keywords: Intraoperative pancreas biopsy; Open surgical biopsy; Pancreatic cancer