An exceptionally rare case of metastatic high-grade urothelial carcinoma of the renal pelvis to the pancreas diagnosed on endoscopic ultrasound-guided fine-needle aspiration: A diagnostic challenge.

Metastases to the pancreas are rare and can be confused with the primary adenocarcinoma of the pancreas. Metastasis of renal pelvis urothelial carcinomas to the pancreas are extremely rare. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) biopsy is a very safe and effective diagnostic method. In this study, we present a 65-year-old male patient with a solitary mass in the pancreas. A moderate cellular tumoral lesion was observed in the aspiration cytology performed from the 55-millimeter solid mass invading the head of the pancreas via EUS-FNA. Tumor cells consisted of cells with irregular borders, different shapes and sizes, hyperchromatic, narrow cytoplasm with dark nuclei, and cells with anisonucleosis in focal areas. Cellblock obtained from aspirated was found diffusely positive with high molecular weight cytokeratin, Thrombomodulin, p63, GATA-3, and CK7, and negative with CK20, PAX8, and PSA. Having a primary malignancy in the medical history of the patients is very important in the differential diagnosis of primary and secondary pancreatic cancers. The potential for metastasectomy in pancreatic metastases can be applied in cases with isolated metastatic disease. Primary tumor histopathology may have an impact on the long-term survival of the case. This study aimed to describe the cytomorphological features of solid and solitary pancreatic malignancies and to evaluate the role of immunohistochemistry performed from aspirate cell block in detecting the primary tumor origin.