Kudo T, Kawakami H, Kuwatani M, Ehira N, Yamato H, Eto K, Kubota K, Asaka M. Three cases of retroperitoneal schwannoma diagnosed by EUS-FNA. World J Gastroenterol 2011; 17(29): 3459-3464 [PMID: 21876639 DOI: 10.3748/wjg.v17.i29.3459]
Corresponding Author of This Article
Hiroshi Kawakami, MD, PhD, Department of Gastroenterology, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-ku, Sapporo, 060-8638, Japan. hiropon@med.hokudai.ac.jp
Article-Type of This Article
Case Report
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Taiki Kudo, Hiroshi Kawakami, Masaki Kuwatani, Nobuyuki Ehira, Hiroaki Yamato, Kazunori Eto, Masahiro Asaka, Department of Gastroenterology, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-ku, Sapporo, 060-8638, Japan
Kazunori Eto, Kanako Kubota, Department of Surgical pathology, Hokkaido University Hospital, Kita 14, Nishi 5, Kita-ku, Sapporo, 060-8638, Japan
Author contributions: Kudo T and Kawakami H contributed equally to this work; Kawakami H managed the patients, performed the endoscopic examination, designed the research and provided discussion of clinical features and pathology; Kuwatani M, Ehira N and Yamato H analyzed the data and provided clinical advice; Eto K and Kubota K diagnosed the case and provided discussion of pathology; Kudo T and Kawakami H collected the data and wrote the paper; Kawakami H revised the paper; Asaka M supervised the research; all authors approved the final manuscript for publication.
Correspondence to: Hiroshi Kawakami, MD, PhD, Department of Gastroenterology, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-ku, Sapporo, 060-8638, Japan. hiropon@med.hokudai.ac.jp
Received: December 16, 2010 Revised: March 4, 2011 Accepted: March 11, 2011 Published online: August 7, 2011
Abstract
Schwannomas are peripheral nerve tumors that are typically solitary and benign. Their diagnosis is largely based on surgically resected specimens. Recently, a number of case reports have indicated that retroperitoneal schwannomas could be diagnosed with endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). We report the diagnosis of three cases of schwannoma using EUS-FNA. Subjects were two males and one female, ages 22, 40, and 46 years, respectively, all of whom were symptom-free. Imaging findings showed well-circumscribed round tumors. However, as the tumors could not be diagnosed using these findings alone, EUS-FNA was performed. Hematoxylin-eosin staining of the resulting tissue fragments revealed bland spindle cells with nuclear palisading. There was no disparity in nuclear sizes. Immunostaining revealed S-100 protein positivity and all cases were diagnosed as schwannomas. Ki-67 indexes were 3%-15%, 2%-3%, and 3%, respectively. No case showed any signs of malignancy. As most schwannomas are benign tumors and seldom become malignant, we observed these patients without therapy. All tumors demonstrated no enlargement and no change in characteristics. Schwannomas are almost always benign and can be observed following diagnosis by EUS-FNA.
