1610 Letters to the Editor The American Journal of GASTROENTEROLOGY VOLUME 104 | JUNE 2009 www.amjgastro.com proliferation of immature plasma cells in the inflamed pouch mucosa of patients with UC (4). In the present case, enhance- ment of humoral immunity by IFN-α administration could have caused dysregu- lation of differentiation of plasma cells that led to the development of severe pouchitis. CONFLICT OF INTEREST Guarantor of the article: Kenichi Morimoto, MD. Specific author contributions: Kenichi Morimoto: planned the study; collected and interpreted data, and draſted the manuscript; Hirokazu Yamagami, Shuhei Hosomi, Mizuki Ohira, Takehisa Suekane, Noriko Kamata, Mitsue Sogawa, and Kenji Watanabe: collected and interpreted data; Kazunari Tominaga, Toshio Watanabe, Yasuhiro Fujiwara, and Akihiro Tamori: interpreted data; Nobuhide Oshitani: collected and interpreted data; Tetsuo Arakawa: interpreted data. Financial support: All authors have no conflict of interest. Potential competing interests: None. REFERENCES 1. Shen B, Achkar JP, Connor JT et al. Modified pouchitis disease activity index: a simplified approach to the diagnosis of pouchitis. Dis Colon Rectum 2003;46:748–53. 2. Sprenger R, Sagmeister M, Offner F. Acute ulcerative colitis during successful interferon/ ribavirin treatment for chronic hepatitis. Gut 2005;54:438–9. 3. Watanabe T, Inoue M, Harada K et al. A case of exacerbation of ulcerative colitis induced by combination therapy with PEGinterferon-2b and ribavirin. Gut 2006;55:1682–3. 4. Hirata N, Oshitani N, Kamata N et al. Proliferation of immature plasma cells in pouchitis mucosa in patients with ulcerative colitis. Inflamm Bowel Dis 2008;14: 1084–90. 1 Department of Gastroenterology, Osaka City University Graduate School of Medicine, Osaka, Japan; 2 Department of Hepatology, Osaka City University Graduate School of Medicine, Osaka, Japan. Correspondence: Kenichi Morimoto MD, Department of Gastroenterology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan. E-mail: moriken@med.osaka-cu.ac.jp Acute Hemorrhage With Retroperitoneal Hematoma After Endoscopic Ultrasound- Fine Guided-Needle Aspiration of an Intraductal Papillary Mucinous Neoplasm of the Pancreas Silvia Carrara, MD 1 , Paolo Giorgio Arcidiacono, MD 1 , Antonella Giussani, MD 1 and Pier Alberto Testoni, PhD 1 doi:10.1038/ajg.2009.132; published online 12 May 2009 To the Editor: Endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) is effective for tissue diagnosis in suspected pancreatic cancer (1) and for collecting fluid from cystic tumors (2). Major complications aſter EUS- FNA of solid masses are rare, but cystic tumors seem to have a higher risk of infection and bleeding. In a series of 50 patients undergoing EUS-FNA of pan- creatic cystic lesions, Varadarajulu and Eloubeidi (3) found acute intracystic hemorrhage at the site of cyst aspiration in three cases (frequency 6%: 95% con- fidence interval 1.3–16.6). ere was no pancreatitis or infectious complications. Clinical history and laboratory param- eters did not predict which patients were at risk for intracystic hemor- rhage (3). A 66-year-old woman presented with multiple pancreatic cysts found by chance during a transabdominal ultrasound. Computed tomography and magnetic resonance imaging confirmed an intraductal papillary mucinous neo- plasm of the main pancreatic duct and side branches involving the whole pan- creas. e largest cyst, measuring 3 cm, was in the tail. EUS-FNA of this cyst was done from the stomach with a 22-gauge fine needle ( Figure 1); 10 ml of clear mucous were aspirated and the cyst col- lapsed completely. Aſter removal of the needle, intracystic hemorrhage occurred at the site of aspiration, manifesting as a fine hyperechoic flow that progressed gradually to involve the entire cyst, then leaked into the retroperitoneal space along the needle path as an expanding echo-rich region ( Figure 2). Color and power Doppler before the puncture had Figure 1. Endoscopic findings for the pouch mucosa. ( a) Pouchitis induced by combination therapy before treatment with metronidazole. Erosions, friable mucosa, and purulent mucus were noted in the pouch. ( b) No erosions were found after treatment with metronidazole.