Leiomyosarcoma of the inferior vena cava, diagnosis by endoscopic ultrasound-guided fine-needle aspiration biopsy

History and admission findings: A 75-year-old woman was admitted because of upper abdominal pain, nausea and vomiting. Investigations: These symptoms were caused by a large tumor of the right retroperitoneal space. Computed tomography and transabdominal ultrasound did not unequivocally determine the site of the mass. Endoscopic ultrasound (EUS) and EUS-guided fine-needle aspiration biopsy (EUS-FNA) ensured safe immunohistochemical diagnosis of a leiomyosarcoma of the inferior vena cava (lVC). Treatment and course: The patient underwent successful enbloc resection of the tumor and the IVC followed by prosthetic reconstruction. Conclusions: This case emphasizes the role of EUS and EUS-FNA in the diagnosis of retroperitoneal lesions. Leiomyosarcoma of the IVC, although rare, should be considered in the differential diagnosis of a retroperitoneal mass.