Endoscopic Ultrasound-Guided Fine Needle Aspiration of Pancreatic Metastases: A Retrospective Study

Abstract

Introduction: Metastatic lesions to the pancreas are an uncommon but increasingly prevalent problem, accounting for 2% of pancreatic malignancies. Surgical resection is often recommended for medically fit patients with a single lesion, but in an era with rapid emergence of new chemotherapies and biologic agents, it has not been well established which modality offers the best survival. Lung, breast, renal, skin, and gastrointestinal origins are the most common metastatic origins. It is postulated that the pancreatic metastases may directly invade the ductal epithelium, causing patients to present similarly to pancreatic adenocarcinoma. We report a cohort of cases at a single medical center that utilizes endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for diagnosis of metastatic lesions to the pancreas. Methods: Medical records were abstracted for patients who underwent EUS-FNA with a diagnosis of pancreatic mass. Data regarding demographics, history, diagnosis, mass characteristics, and outcomes were recorded from patients with metastatic primaries. Results: There were a total number of 1,472 EUS-FNA procedures performed for evaluation of pancreatic mass from 2007-2017. Twenty-two (1.5%) of the masses were found to be from metastatic primaries. Twenty-one were diagnosed with immunocytology after EUS-FNA. Small cell carcinoma of the lung was the most common histopathology (7 of 22; 32%). In the remaining patients, the primary histopathology was lung adenocarcinoma (n=5), renal cell carcinoma (n=4), adenocarcinoma of the breast (n=1), liposarcoma (n=1), neuroendocrine tumor of the rectum (n=1), melanoma (n=1), osteosarcoma (n=1), and squamous cell carcinoma of the lung (n=1). EUS-FNA generated seven new diagnoses of cancer including small cell carcinoma of the lung and adenocarcinoma of the lung. The most common location for metastatic lesions was the pancreatic head (8 of 22; 36%). Four masses were found in the tail of the pancreas, and all were found to be small cell carcinoma of the lung. Four of the patients have documented one year survival. Surgery was performed in three patients. Hospice was pursued by nine of the patients, all with metastases from the lung. Conclusion: Pretherapeutic diagnosis of pancreatic masses due to metastatic primaries is necessary for proper management by the multimodal treatment team. As the treatment of cancer continues to rapidly evolve, EUS-FNA with immunocytology can assist with the diagnosis of pancreatic metastases and have a major clinical role.97_A Figure 1. No Caption available.97_B Figure 2. EUS of pancreatic head with metastatic mass found to be small cell carcinoma of the lung.