title: Cytopathologic diagnosis of oncocytic type intraductal papillary mucinous neoplasm: Criteria and clinical implications of accurate diagnosis.
abstract: BACKGROUND
  Cytologic findings of pancreatic oncocytic-type intraductal papillary mucinous neoplasms (IPMNs)/intraductal oncocytic papillary neoplasms (IOPNs) are largely unknown.
  
  
  METHODS
  Five IOPNs encountered by the authors were analyzed.
  
  
  RESULTS
  Four IOPNs were located in the pancreatic head, and 1 was located in the pancreatic body/tail in 2 men and 3 women ages 56 to 84 years (mean age, 66 years). Radiologic diagnoses included pancreatic ductal adenocarcinoma (PDAC) in 2 patients, invasive cancer associated with IPMN in 1 patient, IPMN versus mucinous cystic neoplasm in 1 patient, and cystic mass in 1 patient. Cytologic findings included: hypercellular smears (4 of 5 cases) containing well formed clusters of oncocytic cells (5 of 5 cases) with prominent, slightly eccentric nucleoli (4 of 5 cases), predominantly arranged in sheets/papillary units (5 of 5 cases), with punched-out intercytoplasmic spaces (4 of 5 cases), and with occasional 3-dimensional groups and focal necrosis (3 of 5 cases). The intracytoplasmic mucin and thick extracellular mucin typical of other IPMNs were observed only in 2 cases and were very limited. The mean size on resection was 4.5 cm. Invasion was observed in 3 cases (0.1, 0.3, and 2.0 cm) of tubular-type IPMN. Initial cytologic evaluation was performed by the authors in 4 of 5 cases, which were diagnosed as IOPN (n = 3) and IPMN versus cystic PDAC (n = 1). One case was initially misdiagnosed as PDAC and, on resection, proved to be noninvasive IOPN.
  
  
  CONCLUSIONS
  Cytologic features of IOPNs are classical, similar to their histologic counterparts, and differ significantly from other IPMN subtypes. Because of their highly complex appearance, they are often radiologically misdiagnosed as PDAC; thus, failure to recognize their characteristic features on fine-needle aspiration may lead to inappropriate treatment. Patients with IOPN have an incomparably better prognosis than patients with ordinary PDAC, even when their neoplasms are invasive.
authors.affiliation: Department of Pathology, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Michelle D
authors.initials: MD
authors.lastname: Reid
authors.affiliation: Department of Pathology, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Christina R
authors.initials: CR
authors.lastname: Stallworth
authors.affiliation: Department of Pathology, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Melinda M
authors.initials: MM
authors.lastname: Lewis
authors.affiliation: Department of Pathology, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Gizem
authors.initials: G
authors.lastname: Akkas
authors.affiliation: Department of Pathology, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Bahar
authors.initials: B
authors.lastname: Memis
authors.affiliation: Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Olca
authors.initials: O
authors.lastname: Basturk
authors.affiliation: Department of Pathology, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Volkan
authors.initials: V
authors.lastname: Adsay
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000175:diagnosis / Q000473:pathology*; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D021441:Carcinoma, Pancreatic Ductal / Q000175:diagnosis / Q000473:pathology*; D015331:Cohort Studies; D003581:Cytodiagnosis / Q000379:methods*; D016208:Databases, Factual; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010180:Pancreatectomy / Q000379:methods; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: cytology; fine-needle aspiration; intraductal oncocytic papillary neoplasm (IOPN); intraductal papillary mucinous neoplasm (IPMN); oncocytic; oncocytic intraductal papillary mucinous neoplasm; pancreas