There is a prominent bulge on the calf to consider benign swelling, bone disease, vascular disease, trauma. 1. Benign masses: such as lipoma, fibroma, sebaceous cysts, mostly benign can be surgically excised, and pathology tests are performed. 2. Bone diseases: such as osteochondroma, bone cysts, bone malignant tumors, such as giant cell tumor of bone, osteosarcoma, can be clearly diagnosed by CT examination, surgical resection, radiotherapy or chemotherapy. 3. Vascular diseases: such as venous sinus, varicose veins, hemangioma, can wear compression stockings, or take surgical treatment. 4. Trauma: If the calf is traumatized, local bleeding can appear as a bulge, local bruising and obvious pressure pain. Calf protruding a bulge need to go to the hospital for examination.