Extraosseous osteosarcoma originating from paratesticular soft tissue is an extremely rare type of malignant tumor. With the exception of the present study, only one other case of osteosarcoma originating from paratesticular soft tissue has previously been reported. A 52-year-old man presented with a painless scrotal swelling and palpable mass. The patient underwent left orchiectomy with the diagnosis of testicular tumor. Pathological examination was suggestive of osteosarcoma without any different histological components. The postoperative course of the patient was uneventful, and the patient is currently free of disease.