Rare Forms Of Osteosarcoma

Rare Forms of Osteosarcoma:

Telangiectatic Osteosarcoma:
– 50 yrs)
– prognosis worse than 1o osteosarcoma

Parosteal Osteosarcoma:
– arises from external surface of bone
– usu in 3rd decade of life involving posterior aspect of distal femur
– presents as painless mass behind the knee
– low-grade malignancy – osteoid & woven trabeculae separated by intervening fibroblasic stroma with minimal cytologic atypia
– wide resection has good local control (80% 5 yr survival) without chemo or radiation
Periosteal Osteosarcoma:
– most common on diaphysis of tibia & femur
– presents as a painful mass
– xrays – ill-defined diaphyseal surface lesion with variable matrix mineralization with a �scooped-out� appearance +/- sunburst reaction or Codman�s triangle
– usu no marrow involvement
– histologically, predominant cartilaginous component with neoplastic osteoid production; lobulated with peripheral condensations of spindle cells
– wide resection with neoadjuvant chemotherapy