Background: Wide resection of malignant bone and soft-tissue tumors of the extremities may impair the functions of the affected limbs. Partial scaplectomy affects shoulder movements, resulting in disabilities that interfere with activities of daily living. Methods: Rehabilitation treatment of a man in his 70s with periscapular malignant soft-tissue tumors subjected to extensive resection with partial scapular resection and split-thickness skin grafting was conducted. Postoperative rehabilitation included early mobilization, range of motion exercises, strength training of the residual muscles, and activities of daily living training. Rehabilitation assessments of physical function, patient-based outcomes, and quality of life were performed preoperatively and at 1, 3, 6 months and 1 year postoperatively. Results: Preoperative function of the affected limb was determined to be 86.7% using the Musculoskeletal Tumor Society Rating Scale score (MSTS), 97.4% using the Toronto Extremity Salvage Score (TESS), and mildly limited in shoulder elevation. The patient was discharged from the hospital approximately 1 month postoperatively. Postoperative shoulder elevation was less than half of the preoperative level, with MSTS in the 30-40% range and TESS in the 60-70% range. Postoperatively, the patient could perform activities of daily living independently, but only with the use of compensatory movements and devices distal to the elbow. Conclusions: After wide tumor resection with loss of skeletal and muscular structures around the shoulder joint including the scapula, postoperative rehabilitation may require maintenance of shoulder immobilization with the residual muscles and efficient use of modified movements distal to the elbow to achieve better function in real-life situations.