Soft tissue tumors are classified into benign and malignant on the basis of the patient's age, medical history, physical examination, pathological and radiologic examination. We have to caution against misdiagnosis of malignant tumor which can delay the treatment time. Lipoma, schwannoma, hemangioma, and ganglion cysts are common benign tumors, usually of small size and are often located in the superficial layer. Although it may be suspected as a benign tumor, performing contrast-enhanced magnetic resonance maging is preferably advantageous. Liposarcoma and undifferentiated pleomorphic sarcoma, the most common malignant soft tissue tumors, usually occur after middle age; rhabdomyosarcoma is usually presented in children and synovial sarcoma often occurs at a younger age. The magnetic resonance (MR) signal intensity of lipoma shows uniformity with subcutaneous fat, sarcoma should be suspected if it has a contrast-enhanced and non-fat-suppressed part. The MR signals of ganglion cysts show homogeneous and same signal intensity with joint fluid and urine, while the liquid containing sarcoma, like synovial sarcoma, is characterized by heterogeneous signal intensity and contrast enhancement. If surgery is performed, an incision should be made in the longitudinal direction of the limb and the excised tumor should be sent for pathology analysis. When the macroscopic finding of the tumor during surgery is different from the expected diagnosis, the operation should cease with biopsy only or the small superficial tumor can be excised widely if possible. The transfer should be considered unless you can be sure of a benign tumor in hands and feet of children. When diagnosed as malignant tumors, patients should be provided with sufficient information that can lead them to a musculoskeletal tumor specialist.