Multidisciplinary surgical management with chemotherapy and transcatheter arterial embolization for a giant hypervascular pancreatic neuroendocrine tumor.

Pancreatic neuroendocrine tumors (pNETs) are rare and heterogeneous neoplasms occasionally presenting as giant, hypervascular, and anatomically complex tumors. In such cases, curative resection is often challenging, and multidisciplinary treatment is required. However, the clinical utility and optimal sequencing for these approaches remain unclear. We report a 39-year-old woman with a 130 mm hypervascular pNET occupying nearly the entire pancreas, complicated by portal vein tumor thrombus (PVTT) and extensive collateral circulation. The tumor was initially deemed unresectable by a multidisciplinary team. Streptozotocin (STZ)-based chemotherapy led to tumor regression and PVTT resolution. Preoperative transcatheter arterial embolization (TAE) was subsequently performed to reduce arterial inflow and facilitate surgical manipulation. Total pancreatectomy with segmental portal vein resection was successfully performed without transfusions. Histopathological examination confirmed a grade 2 pNET with a multifocal histological response which was consistent with radiological findings. The patient remained recurrence-free for 12 months postoperatively without adjuvant therapy. This case highlights the clinical utility of integrating STZ-based chemotherapy and selective TAE to achieve curative surgery for locally advanced giant pNETs. The unique clinical course and radiologic-pathologic correlation of this rare disease further contribute to the understanding of the treatment response.