[Inaugural cutaneous metastases of an osteosarcoma: a case report].

Inaugural cutaneous metastasis is exceptional in osteosarcoma. We report a case of a woman with osteosarcoma of the right knee who presented two tumefactions of the scalp at the time of diagnosis. Magnetic resonance imaging identified a high intensity T2 signal in the femur and also a high-intensity signal in the soft tissues. The head scan confirmed the presence of two subcutaneous tumors. Biopsy of the two sites demonstrated the metastatic nature of the cutaneous lesions. The patient was given preoperative and postoperative chemotherapy. Wide resection followed by prosthesis reconstruction was performed. Pulmonary metastases developed and led to two thoracotomy procedures. The patient has remained in remission 22 months. Six cases of cutaneous metastases of osteosarcoma have been reported in the literature. The cutaneous metastases were secondary in five of six cases, occurring after other metastatic localizations had been discovered. The present case is the first published observation of synchronous cutaneous metastases. The duration of remission suggests that cutaneous localizations should be treated like other inaugural metastatic localizations with intensive chemotherapy and wide resection of the primary tumor.