Endoscopic ultrasound-guided fine needle aspiration cytology of metastatic renal cell carcinoma to the pancreas: A multi-center experience

Introduction: The increasing use of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) cytology to examine pancreatic neoplasms has led to an increase in the diagnosis of metastases to the pancreas. Renal cell carcinoma (RCC) is the most common metastasis to the pancreas. Our study examines 33 cases of metastatic RCC to the pancreas sampled by EUS-FNA from four large tertiary care hospitals. Materials and Methods: We searched the cytopathology database for RCC metastatic to the pancreas diagnosed by EUS-FNA from January 2005 to January 2015. Patient age, history of RCC, nephrectomy history, follow-up postnephrectomy, radiological impression, and EUS-FNA cytologic diagnosis were reviewed. Results: Thirty-three patients were identified. The average age was 67.5 years (range, 49-84 years). Thirty-two patients had a previous documented history of RCC. One patient had the diagnosis of pancreatic metastasis at the same time of the kidney biopsy. Thirty-one patients had been treated with nephrectomy. Twenty-seven patients were being monitored annually by computed tomography or magnetic resonance imaging. Twenty-five patients had multiple masses by imaging, but 8 patients had a single mass in the pancreas at the time of EUS-FNA. EUS-FNA of 20 cases showed classic morphology of RCC. Thirteen cases had either "atypical" clinical-radiologic features or morphologic overlaps with primary pancreatic neoplasms or other neoplasms. Cell blocks were made on all 13 cases and immunochemical stains confirmed the diagnosis. Conclusions: EUS-FNA cytology is useful for the diagnosis of metastatic RCC to the pancreas. Cytomorphology can be aided with patient history, imaging analyses, cell blocks, and immunochemical stains.