title: Large retroperitoneal isolated fibrous cyst in absence of preceding trauma or acute pancreatitis.
abstract: BACKGROUND
  Isolated retroperitoneal cystic masses are uncommon with an estimated incidence of 1/5750 to 1/250,000. The majority present with size related symptoms, complications, or a mass. Approximately a third of patients are asymptomatic and are diagnosed incidentally. Aetiologies of retroperitoneal cystic masses (RPC) include mesenteric, omental, splenic and enteric duplication cysts. Neoplastic RPCs can be divided into epithelial (mucinous or serous cystadenoma), mesothelial (mesothelioma), germ cell (cystic teratoma) and cystic changes in a solid neoplasm (paraganglioma, neurilemmoma, sarcoma).
  
  
  METHODS
  A 53 year-old man presented to us with abdominal pain related to a large mass in his left upper quadrant with associated anorexia and weight loss. He gave no history of previous trauma and denied having symptoms or a history of pancreatitis. He said he had felt this mass increasing in size over the course of several years. Clinical examination of his abdomen revealed a large firm left sided mass extending to his left upper quadrant. Imaging with computed tomography (CT) and magnetic resonance imaging cholangio-pancreatogram (MRCP) revealed a 13.7 cm × 12.2 cm × 10.9 cm cystic lesion in the retroperitoneum which was separate from the kidney, pancreas, spleen and bowel. At laparotomy, this mass was easily dissected from the surrounding viscera and was excised completely intact. Histopathological assessment found the mass to be a large fibrous pseudocyst with no epithelial lining.
  
  
  CONCLUSIONS
  We present a rare case of an isolated large retroperitoneal fibrous pseudocyst unrelated to previous pancreatitis which was successfully managed with surgery.
authors.affiliation: Division of Surgery, University of Western Sydney, Sydney, Australia.
authors.forename: Julie
authors.initials: J
authors.lastname: Ahn
authors.affiliation: Division of Surgery, University of Western Sydney, Sydney, Australia.|Upper Gastrointestinal Unit, Bankstown Hospital, Sydney, Australia.
authors.forename: Manju D
authors.initials: MD
authors.lastname: Chandrasegaram
authors.affiliation: Upper Gastrointestinal Unit, Bankstown Hospital, Sydney, Australia.
authors.forename: Khaled
authors.initials: K
authors.lastname: Alsaleh
authors.affiliation: Division of Surgery, University of Western Sydney, Sydney, Australia.|Upper Gastrointestinal Unit, Bankstown Hospital, Sydney, Australia.
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Woodham
authors.affiliation: Upper Gastrointestinal Unit, Bankstown Hospital, Sydney, Australia.
authors.forename: Adrian
authors.initials: A
authors.lastname: Teo
authors.affiliation: Upper Gastrointestinal Unit, Bankstown Hospital, Sydney, Australia.
authors.forename: Amithaba
authors.initials: A
authors.lastname: Das
authors.affiliation: Division of Surgery, University of Western Sydney, Sydney, Australia. neil.merrett@sswahs.nsw.gov.au.|Upper Gastrointestinal Unit, Bankstown Hospital, Sydney, Australia. neil.merrett@sswahs.nsw.gov.au.
authors.forename: Neil D
authors.initials: ND
authors.lastname: Merrett
authors.affiliation: Upper Gastrointestinal Unit, Bankstown Hospital, Sydney, Australia.
authors.forename: Christos
authors.initials: C
authors.lastname: Apostolou
mesh_terms: D003560:Cysts / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012187:Retroperitoneal Space; D014057:Tomography, X-Ray Computed