Leiomyosarcoma is a rare malignant soft-tissue tumor whose cells resemble smooth-muscle tissue. It has been reported to arise in different areas of the head and neck region. Primary leiomyosarcoma of the parapharyngeal space, however, is extremely rare, as only 4 cases have been previously reported to date. We describe the somewhat urgent case of a primary leiomyosarcoma of the right parapharyngeal space in a 30-year-old man. We also review the diagnostic and therapeutic challenges that clinicians face in managing this rare tumor.