Retroperitoneal, Liver, and Lymph Node Metastasis from Proximal Tibial Osteosarcoma: A Case Report.

The present study describes the case of a male adult with an osteosarcoma in the proximal tibia, treated with limb salvage with endoprosthesis and chemotherapy. The patient developed an unusual metastatic pattern compromising the liver, bone, and inguinal lymph nodes, without local recurrence in the tibia or pulmonary metastases. Osteosarcoma (OS) is the second most frequent primary bone tumor after multiple myeloma in adults. Frequent sites of metastases in case of disease progression are the lungs and bone. Extrapulmonary metastases are rare. The development of new schemes of chemotherapy have improved life expectancy in osteosarcoma patients but have also altered the usual patterns of metastases, resulting in unusual metastatic locations.