Metastatic hepatocellular carcinoma presenting as a pancreatic mass by computed tomography scan and mimicking a primary neuroendocrine tumor: a potential pitfall in aspiration cytology.

Hepatocellular carcinoma (HCC) is a highly malignant neoplasm, often presenting at late stage and portending et poor prognosis,for the patient. The peripancreatic fat is a rare site of extrahepatic metastasis, and metastatic HCC can mimic primary pancreatic neoplasms, even in this location. It is crucial to be aware of this pitfall in the evaluation of aspiration cytology of pancreatic neoplasms and to develop a strategy to reach the correct diagnosis. We present an endoscopic ultrasound fine-needle aspiration diagnosis of metastatic HCC presenting as a pancreatic mass radiologically that had neuroendocrine features on various cytological and histological preparations. The metastatic lesions were located surgically in the peripancreatic adipose tissue with involvement of one peripancreatic lymph node. This case illustrates the utility of FNA for diagnosing uncommon presentations of HCC and the importance of clinical history, cell block, and an immunocytochemical panel in determining the origin of the tumor. Diagn. Cytopathol. 2009;37:915-919. (C) 2009 Wiley-Liss, Inc.