title: Pitfalls in fine needle aspiration cytology of extraadrenal paraganglioma. A report of 2 cases.
abstract: BACKGROUND
  Fine needle aspiration (FNA) is commonly used as an initial diagnostic tool in the evaluation of mass lesions. However, extraadrenal paragangliomas (EAPs) are not commonly seen on FNA and, when encountered, can pose a diagnostic challenge since they have a wide variety of morphologic patterns.
  
  
  METHODS
  Two intraabdominal EAPs were misdiagnosed as an anaplastic adenocarcinoma of the pancreas with giant cell features and papillary adenocarcinoma of the pancreas. The sources of the pitfalls were inaccurate radiologic localization, misinterpretation of vascular-rich tissue fragments as papillary structures, presence of acinarmicroglandular structures, marked cellular pleomorphism (including multinucleation), prominent nucleoli and some cells with "squamoid" cytoplasm.
  
  
  CONCLUSIONS
  The cytologic features of EAP, although suggestive, are not specific. A high index of suspicion and knowledge of clinical information, exact anatomic location and cytologic morphology combined with appropriate ancillary studies are the key to an accurate diagnosis.
authors.affiliation: M. D. Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Yun
authors.initials: Y
authors.lastname: Gong
authors.forename: Denise V
authors.initials: DV
authors.lastname: DeFrias
authors.forename: Ritu
authors.initials: R
authors.lastname: Nayar
mesh_terms: D000368:Aged; D044963:Biopsy, Fine-Needle / Q000592:standards; D002277:Carcinoma / Q000000981:diagnostic imaging / Q000473:pathology*; D003937:Diagnosis, Differential; D003951:Diagnostic Errors / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000556:secondary; D009362:Neoplasm Metastasis / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D010236:Paraganglioma, Extra-Adrenal / Q000000981:diagnostic imaging / Q000473:pathology*; D011123:Polyploidy; D012186:Retroperitoneal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed