Pancreatic neuroendocrine tumor with splenic vein tumor thrombus: A case report

Pancreatic neuroendocrine tumors (PNET) are rare, often indolent malignancies. PNET are classified as functional or nonfunctional based on the secretion of hormones without a negative feedback loop; the latter account for up to 60% of PNET. Although PNET are associated with a better prognosis compared to pancreatic adenocarcinomas, they are often diagnosed in advanced stages, making them a significant source of morbidity for patients. Here we present a rare case of venous tumor thrombus arising from a nonfunctional PNET.

A 44-year-old woman was referred for evaluation and treatment of a possible tail of pancreas PNET discovered during work-up for a 9 year history of intermittent subcostal pain. Previous endoscopic ultrasound with fine needle aspiration revealed a 3.5cm×3cm mass, with cytological diagnosis of neuroendocrine tumor. Patient was scheduled for laparoscopic distal pancreatectomy. During surgery the mass was found to encase the splenic vein leading the surgeon to perform an en bloc distal pancreatectomy and splenectomy. Pathologic analysis revealed a 1.8cm×5cm tumor thrombus lodged in the splenic vein.

Nonfunctional PNET usually present in advanced stages and can be associated with venous tumor thrombi. Preoperative imaging may not accurately predict the presence of venous tumor thrombi.

En bloc resection of primary tumor, involved organs and thrombus is the recommended treatment option and often results in long term survival. New multi-modality strategies are needed for detection of venous involvement in nonfunctional PNET to better assist with preoperative planning and counseling.