Fine-Needle Aspiration Biopsy Diagnosis of Oncocytic Carcinoma of the Pancreas

Abstract

Oncocytic carcinoma of the pancreas is a very rare variant of pancreatic ductal adenocarcinoma. Fine-needle aspiration biopsy reports of this tumor are exceptionally rare. We report the case of a 65-year-old female patient who presented with a mass in the head of the pancreas. The mass was sampled by fine-needle aspiration biopsy on 2 separate occasions, and both samples were diagnosed as oncocytic carcinoma of the pancreas. The patient underwent a Whipple resection, and histopathologic examination of the resection specimen showed an invasive oncocytic carcinoma arising from intraductal oncocytic papillary neoplasm with highgrade dysplasia. Here we discuss the cytologic and histological features, differential diagnoses, utility of ancillary studies, and the recently updated knowledge about this rare entity.A s a very rare variant of pancreatic ductal adenocarcinoma (PDAC), oncocytic carcinoma of the pancreas has distinctive histological and cytologic features. Arising from the oncocytic subtype of the intraductal papillary mucinous neoplasm (IPMN-O), 1 also known as intraductal oncocytic papillary neoplasm, it was first described by Adsay et al 2 in 1996. The oncocytic subtype of IPMN is a very rare form of IPMN (<5% of all IPMNs), 3 consisting of complex, arborizing papillary intraductal projections of cuboidal cells with finely granular oncocytic cytoplasm, and diffusely present goblet cells. Oncocytic carcinoma of the pancreas is thought to be a subtype of PDAC; however, several reports have indicated that patients with oncocytic carcinoma have significantly better outcomes than do those with classic PDAC (median survival of 132 months for oncocytic carcinoma vs 18 months for PDAC). 1,4-6 Moreover, KRAS mutations, which are seen in more than 90% of PDACs, were rare in oncocytic carcinomas (20%). 1 The different prognostic and molecular features may lead to different therapeutic interventions. Therefore, it is essential to accurately diagnose this entity, especially on preoperative sampling. However, because of its rarity, oncocytic carcinoma of pancreas has been reported only in single case reports and small series. Reports describing the cytologic features in 4 prior cases are summarized in Table 1. [7][8][9] Here we report the case of a patient presenting with oncocytic carcinoma of the pancreas, which was diagnosed preoperatively by fine-needle aspiration biopsy (FNAB). Its morphological features, ancillary study results and follow-up information are described to enrich our understanding of this neoplasm. CASE REPORTThis case report is conducted following the guidelines of the Scientific Review Board of Moffitt Cancer Center and the institutional review board of the University of South Florida.A 65-year-old woman presented to an outside institution with an unexplained 25-lb weight loss and acute cholecystitis. Magnetic resonance cholangiopancreatography was performed to assess her biliary system for possible common bile duct stones. At magnetic resonance cholangiopancreatography, dilation of the main pancre...