Falling under the umbrella cells: A single institutional experience and literature review of urothelial carcinoma presenting as a primary pancreatic mass on endoscopic ultrasound-guided fine-needle aspiration

Malignant biliary obstruction due to metastatic non-hepato-pancreato-biliary cancer

Malignant biliary obstruction generally results from primary malignancies of the pancreatic head, bile duct, gallbladder, liver, and ampulla of Vater. Metastatic lesions from other primaries to these organs or nearby lymph nodes are rarer causes of biliary obstruction. The most common primaries include renal cancer, lung cancer, gastric cancer, colorectal cancer, breast cancer, lymphoma, and melanoma. They may be difficult to differentiate from primary hepato-pancreato-biliary cancer based on imaging studies, or even on biopsy. There is also no consensus on the optimal method of treatment, including the feasibility and effectiveness of endoscopic intervention or surgery. A thorough review of the literature on pancreato-biliary metastases and malignant biliary obstruction due to metastatic non-hepato-pancreato-biliary cancer is presented. The diagnostic modality and clinical characteristics may differ significantly depending on the type of primary cancer. Different primaries also cause malignant biliary obstruction in different ways, including direct invasion, pancreatic or biliary metastasis, hilar lymph node metastasis, liver metastasis, and peritoneal carcinomatosis. Metastasectomy may hold promise for some types of pancreato-biliary metastases. This review aims to elucidate the current knowledge in this area, which has received sparse attention in the past. The aging population, advances in diagnostic imaging, and improved treatment options may lead to an increase in these rare occurrences going forward.

An Unusual Case of Urothelial Cell Carcinoma With Metastasis to the Pancreas

Metastasis to the pancreas is far less common than primary pancreatic tumors. Bladder cancer metastasis involving the pancreas is rarely reported. Here, we report a case of metastasis to the pancreas of urothelial cell origin, diagnosed via upper endoscopic ultrasound-guided fine-needle aspiration and biopsy, and coupled with immunostaining. A high index of suspicion must be maintained for atypical metastatic locations of urothelial cell carcinoma, especially to the pancreas.