A Primary Keratinizing Squamous Cell Carcinoma of the Pancreas: Endosonography and Confocal Endomicroscopy of an Unusual Pancreatic Cystic Lesion

Abstract

Case Report: A 79-year-old woman presented with abdominal discomfort and unintentional weight loss. A computed tomography scan demonstrated a 7 cm complex pancreatic cystic lesion (PCL) along with multiple hepatic cystic lesions. Endoscopic ultrasound (EUS) demonstrated a 7.1 x 6.7 cm anechoic cystic lesion with an irregularly thick wall and multiple mural nodules in the pancreatic body without obvious communication with the main pancreatic duct. On protocol, EUS-guided needle-based confocal laser endomicroscopy (nCLE) with an AQ-Flex 19 miniprobe (Cellvizio, Mauna Kea Technologies, Paris, France) revealed large cells of unequal shapes and sizes (> 20 μ) suggestive of a malignant process. Fine needle aspiration (FNA) confirmed a diagnosis of pancreatic keratinizing squamous cell carcinoma (SCC) metastatic to liver with demonstration of irregular spindle-like cells, hyperchromatic cells, and dense keratin material from both the primary pancreatic and metastatic liver lesions. Discussion: A primary pancreatic SCC constitutes a rare diagnosis with very few reports described in the literature. One large case series reviewed 5075 patients and reported the incidence of pure squamous cell carcinoma 0.5% of the total pancreatic ductal carcinomas1. Moreover, this case is unique for being an unusual presentation of a PCL where the diagnosis of malignancy was suspected by EUS-nCLE and confirmed with FNA. This adds to the growing literature of intracystic nCLE image patterns in the diagnosis of PCLs. 1) Baylor SM, Berg JW. Cross-classification and survival characteristics of 5,000 cases of cancer of the pancreas. J Surg Oncol 1973;5:335-358.