S3341 A Rare Face in a Familiar Place: Squamous Cell Carcinoma of the Pancreatic Head

Introduction: Squamous cell carcinoma (SCC) of the pancreas is exceptionally rare, with few cases reported in the literature. We describe a case of a 66-year-old woman with a history of pulmonary SCC who presented with a pancreatic mass later confirmed as SCC. The case illustrates the diagnostic and therapeutic complexities associated with rare malignancies and atypical metastatic patterns. Case Description/Methods: The patient was initially diagnosed with a right lower lobe pulmonary mass, histologically confirmed as well-differentiated SCC. Positron emission tomography scan revealed a 4.5 cm intensely fluorodeoxyglucose-avid mass with central necrosis and subcarinal lymphadenopathy. She completed 6 cycles of chemotherapy carboplatin and paclitaxel and 30 sessions of radiation by 7/2024. Plans for immunotherapy were deferred due to clinical complications 2 months after her chemoradiation and during a subsequent hospitalization, a computed tomography scan incidentally revealed a pancreatic head mass and regional lymphadenopathy. Notably, imaging from April 2024 had shown no pancreatic abnormalities. Given the rarity of pancreatic metastases from lung SCC, further evaluation was initiated. Positron emission tomography imaging and a gastroenterology consult were pursued. Endoscopic ultrasound identified a 30 × 24 mm mass in the pancreatic head. Fine needle aspiration confirmed poorly differentiated carcinoma with features consistent with SCC. While the findings are suggestive of metastasis from the known lung primary, primary pancreatic SCC-though exceedingly rare-could not be definitively ruled out. Eventually metastatic SCC was confirmed with immunohistochemistry. Discussion: This case underscores the complexity of diagnosing rare metastatic presentations. The pancreatic lesion emerged rapidly, with no prior imaging evidence just months earlier, suggesting an aggressive disease course. Histologic findings were consistent with SCC, matching the patient’s known pulmonary primary, though the rare possibility of a primary pancreatic SCC remains. Pancreatic metastasis from lung SCC is extremely uncommon, complicating both diagnosis and treatment. The patient’s treatment was further challenged by prior complications that delayed immunotherapy. Standard treatment avenues have largely been exhausted, necessitating a multidisciplinary approach to manage both the primary lung cancer and the new pancreatic involvement This report highlights a rare and aggressive presentation of lung SCC with suspected pancreatic metastasis. It emphasizes the need to maintain a high index of suspicion for atypical metastatic patterns in cancer patients.