Decoding Femoral Vein Leiomyosarcoma: A Rare Vascular Malignancy Revealed Through Imaging

Lumps are commonly found in the femoral triangle. Femoral hernias and lymphadenopathy are included in the differential diagnosis. One of the rare possibilities of femoral triangle swellings is leiomyosarcoma. Leiomyosarcoma originating from the walls of blood vessels is very rare, and only a few cases are reported. We present a case of a 50-year-old male patient complaining of swelling over the left thigh. Ultrasonography showed a highly vascular soft tissue tumour in the anteromedial compartment of the thigh. Magnetic resonance imaging (MRI) was done later. It showed a well-defined, heterogeneously enhancing solid cystic lesion along the femoral vein with intravenous extension, and the femoral artery was seen encasing along its length. A surgical exploration of the lesion suggested a mass originating from the femoral vein, obstructing the vein itself. The mass was excised, and the defect in the vein was repaired. Histopathological examination revealed the mass to be leiomyosarcoma of vascular origin.