Endoscopic ultrasound-guided fine-needle biopsy diagnosing pancreatic metastasis seven years after renal leiomyosarcoma resection: a case report

Renal leiomyosarcoma metastasis to the pancreas is exceptionally rare. Here, we present a case of metastatic recurrence in the pancreas seven years after renal leiomyosarcoma resection. A 73-year-old female with a history of renal leiomyosarcoma surgery seven years prior presented with a well-defined 40 × 30 mm pancreatic tail tumor detected by a computed tomography (CT) scan. The tumor exhibited hypo-enhancement in the arterial phase and a progressive enhancement pattern toward the equilibrium phase, similar to pancreatic cancer. Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) revealed bundles of spindle cells that matched those in the previously resected renal sample. Immunohistochemistry showed positive staining for desmin, confirming the diagnosis of pancreatic metastasis from renal leiomyosarcoma. The patient underwent a distal pancreatectomy to remove the metastatic lesion. The extended interval of seven years before the detection of metastasis underscores the challenges in monitoring and diagnosing metastatic patterns of renal leiomyosarcoma. EUS-FNB can assist in distinguishing metastatic pancreatic leiomyosarcoma from primary pancreatic cancer, thus influencing treatment decisions.