Primary inferior vena cava smooth muscle tumor with diffuse bizarre giant nuclei and low mitotic rate: a nomenclatural conundrum

However, current thinking based on location in the IVC and the presence of any mitotic activity with cellular atypia makes this lesion a leiomyosarcoma. Perhaps more pragmatic terminology would be smooth muscle tumor with bizarre nuclei and low malignant potential since the limited number of cases described thus far appear to have a more indolent course.