First Histologically Confirmed Lymph Node Metastasis in Leiomyosarcoma of the Inferior Vena Cava at the Time of Initial Surgery: Clinical Implications for Surgical Strategy.

ObjectivesLeiomyosarcoma of the inferior vena cava (IVC-LMS) is a rare vascular sarcoma that typically spreads hematogenously, while lymphatic dissemination is exceedingly uncommon. This report presents the first histologically confirmed patient with regional lymph node metastasis in leiomyosarcoma of the IVC detected at the time of initial surgery.MethodsA 60-year-old woman presented with abdominal and back pain. Preoperative imaging revealed a retroperitoneal mass encasing the IVC, initially suspected to be lymphoma. The patient underwent en bloc resection of the tumor with the IVC and aortic graft replacement. Histopathologic and immunohistochemical analyses were performed to confirm tumor type and assess lymphatic involvement.ResultsHistology showed spindle-shaped tumor cells with nuclear pleomorphism and positivity for desmin and α-smooth muscle actin, confirming leiomyosarcoma. A regional lymph node exhibited metastatic infiltration, verified by hematoxylin and eosin and D2-40 immunostaining. Despite complete resection, the disease recurred within 2 weeks and metastasized to the lungs, liver, and peritoneum within 5 months. The patient died 11 months after surgery.ConclusionsThis report provides the first histologic evidence of lymphatic metastasis in leiomyosarcoma of the IVC, challenging the traditional view that lymphatic spread is negligible in this disease. Selective lymph node evaluation may improve staging accuracy and guide surgical planning for high-risk patients.