title: Duodenal duplication cyst with profound elevation of intracystic carbohydrate antigen (CA 19-9) and carcinoembryonic antigen (CEA): a rare but important differential in the diagnosis of cystic tumours of the pancreas.
abstract: BACKGROUND
  Enteric duplication cysts are rare lesions of uncertain incidence and natural history. Pre-operative confirmation of diagnosis can be difficult. This case reports an adult duodenal duplication cyst presenting with grossly elevated intra-lesional levels of tumour markers.
  
  
  METHODS
  A 57-year-old female was found to have a complex cystic lesion of the head of the pancreas. Intra-lesional fluid analysis revealed a grossly elevated CA 19-9 and CEA. Resection was undertaken under the assumption that this was a cystic tumour. Macroscopic examination after opening the duodenum revealed a villous, circumferential tumour in the proximal duodenum measuring 4 cm in length. A cystic lesion was present in the medial wall of the tumour and did not communicate with the duodenal lumen. Microscopically, the tumour comprised Brunner's gland hyperplasia with associated mucosal thickening. The wall of the underlying cystic lesion was comprised of muscularis formed by the outer muscle coat of the duodenal wall. The final diagnosis was of a duodenal duplication cyst. There was no evidence of dysplasia or malignancy.
  
  
  CONCLUSIONS
  This is the first report of a duodenal duplication cyst having elevated intra-cyst fluid levels of amylase, carbohydrate antigen CA 19-9 and carcinoembryonic antigen (CEA). Although rare, this is an important differential diagnosis in the management of cystic tumours of the pancreas.
authors.affiliation: Hepatobiliary Unit, Department of Surgery, Manchester Royal Infirmary, Manchester, United Kingdom.
authors.forename: Kant J
authors.initials: KJ
authors.lastname: Shah
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Malleo
authors.forename: Jee
authors.initials: J
authors.lastname: Low
authors.forename: Kassiani
authors.initials: K
authors.lastname: Skordilis
authors.forename: Alistair J
authors.initials: AJ
authors.lastname: Makin
authors.forename: Ajith K
authors.initials: AK
authors.lastname: Siriwardena
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D018395:CA-19-9 Antigen / Q000032:analysis*; D002272:Carcinoembryonic Antigen / Q000032:analysis*; D003560:Cysts / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D004378:Duodenal Diseases / Q000000981:diagnostic imaging; D004386:Duodenum / Q000002:abnormalities*; D005260:Female; D006801:Humans; D008875:Middle Aged; D010181:Pancreatic Cyst / Q000175:diagnosis* / Q000000981:diagnostic imaging; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery; D014057:Tomography, X-Ray Computed
chemical_list: D014408:Biomarkers, Tumor; D018395:CA-19-9 Antigen; D002272:Carcinoembryonic Antigen