Pancreatic metastasis of primary lung adenocarcinoma is a rare occurrence, accounting for <0.3% of all pancreatic malignancies. Given that the prognosis and treatment options for primary pancreatic cancer differ greatly from pancreatic metastases from a primary site, an accurate diagnosis is critical. This report presents a unique case of a 65-year-old man who was admitted with significant unintentional weight loss, fatigue, abdominal pain, and jaundice, and found to have a pancreatic mass initially thought to be primary pancreatic adenocarcinoma and subsequently diagnosed as an EGFR-mutated lung adenocarcinoma with metastases to the pancreas via early application of next-generation sequencing (NGS). The use of NGS early in the patient’s clinical course not only changed the treatment strategy but also drastically altered the prognosis. Although metastatic pancreatic adenocarcinoma has a poor prognosis and survival rate, treatment of EGFR-mutated non–small cell lung cancer with EGFR tyrosine kinase inhibitors is associated with high response rates. Importantly, our case demonstrates that timely application of NGS very early in the disease course is paramount to the diagnosis, management, and prognosis of solid malignancies.