Soft-tissue metastasis of osteosarcoma to the submental vestibule

A case of metastatic osteosarcoma in the submental vestibule of the oral cavity and the lung is described in an 18-year-old male with primary osteosarcoma occurring in the sacrum. Dissemination of osteosarcoma to other organs, especially early to the lung, is common, but its metastasis to the oral mucosa has been rarely reported. The patient presented 6 years after initial diagnosis, suggesting the need for careful long-term follow-up of patients with osteosarcoma. This case also illustrates that immunohistochemical staining of osteocalcin is useful to confirm the histological diagnosis of oral soft-tissue metastasis.