Extraskeletal osteosarcoma of subcutaneous soft tissue with lymph node and skin metastasis: a case report with fluorescence in situ hybridization analysis.

摘要

Osteosarcomas represent the 35% of all malignant bone neoplasms and affect mainly children and young adults [1]. Their principal histopathologic feature is the production of osteoid or bony matrix by the tumor cells [2]. Extraskeletal osteosarcoma (EOS) arises from mesenchymal cells of soft tissues and accounts for approximately 2-4% of all osteosarcomas [3]. Unlike its skeletal counterpart, EOS occurs primarily in adulthood (5th to 7th decades of life). The thigh, buttock, upper extremity and retroperitoneum are the most common anatomic locations [3-5]. EOS has a very poor prognosis, and 75% of the patients die within 5 years of the initial diagnosis. In 60% of the cases they develop metastases, mainly to the lungs and bones [4].Although osteosarcoma is one of the few sarcomas that develop regional lymph node metastases, metastasis of a soft tissue EOS to the skin and subcutaneous soft tissue are extremely uncommon. In this report, we describe a case of a primary subcutaneous EOS with skin and subcutaneous metastasis.