Diagnosis of primary squamous cell carcinoma of the pancreas using endoscopic ultrasound-guided core needle biopsy

Primary squamous cell carcinoma (SCC) of the pancreas is a particularly rare entity. Diagnosis of this tumor is tentatively made after ruling out metastatic SCC from another primary site and adenosquamous carcinoma (ASC) of the pancreas. Here we discuss the case of a 76-year-old woman who was found to have a solitary pancreatic lesion and multiple hepatic lesions. Results of computed tomography-guided biopsy of the liver lesions were consistent with a metastatic carcinoma displaying squamous differentiation; therefore, an endoscopic ultrasound (EUS)-guided core-needle biopsy (CNB) of the pancreatic mass was performed. Meticulous histopathological examination of the pancreatic specimen at multiple levels revealed moderately well-differentiated SCC with no glandular component. An extensive metastatic work-up did not reveal an extra-pancreatic origin for this SCC; hence, a diagnosis of primary SCC of the pancreas was established. To our knowledge, this is the first report of the diagnosis of a primary SCC of the pancreas using EUS-guided CNB. We believe that CNB has a diagnostic yield equivalent to that of fine-needle aspiration for recognizing pancreatic adenocarcinoma; however, when cytological examinations reveal atypical squamous epithelial cells suggestive of malignancy, CNB may provide a better tissue specimen, from which to determine the presence of a glandular component. Such an assessment will differentiate pancreatic SCC from ASC.