Reconstruction using a frozen autograft for a skull and humeral lesion of synchronous multicentric osteosarcoma after undergoing successful neoadjuvant chemotherapy: a case report and review of the literature.

An early correct diagnosis, the proper management of chemotherapy, and surgical treatment for all lesions are essential for achieving a good clinical outcome, even in SMOS including a skull lesion. By performing reconstruction using a frozen autograft for a proximal humeral lesion and a skull lesion after confirming the good histological efficacy of neoadjuvant chemotherapy for the primary lesion, the excellent function of the shoulder joint and a good cosmetic outcome at the site of the skull lesion was acquired without complications or recurrence.