Liposarcomas are one of the most common soft-tissue sarcomas and commonly arise in the deep soft tissues of the extremities and retroperitoneum; however, the occurrence of liposarcomas in the foot or ankle is exceedingly rare. In this article, we present a 52-year-old man with round cell liposarcoma arising in the left foot. This tumor presented unusual manifestations of secondary osseous involvement in the metatarsal and tarsal bones of the left foot and solitary lymph node metastasis at the para-aortic region. Magnetic resonance imaging (MRI) and [(18)F]-fluoro-deoxy-glucose positron emission tomography computed tomography (FDG PET-CT) evaluation was considered to be useful for tumor grading and staging in this case.