“…In general, primary venous leiomyosarcoma usually is found in the inferior vena cava and lower extremity veins. In 1992, Dzsinich et al 9 conducted a retrospective study of 210 cases of primary venous leiomyosarcoma and reported that approximately 33% of cases occurred in lower extremity veins, with most tumors found in the great saphenous veins, femoral veins, external iliac veins, and popliteal veins. Leiomyosarcoma mainly originates from vascular smooth muscle cells, and the typical microscopic manifestations include disordered arrangement of muscle fibers and small spindle cells, with positive staining for eosinophilic cytoplasm, desmine, and actine, of which the latter 2 are immunohistochemical staining markers of smooth muscle cells.…”