A unique case of parosteal osteosarcoma (POS) of the proximal femur, with areas of telangiectatic dedifferentiation, in a 28-year-old woman is reported. The patient had a 7-week history of pain and swelling in her right thigh. A biopsy diagnosis of POS was established. The patient was treated with two cycles of intra-arterial chemotherapy, followed by limb salvage surgery. Histological examination of the resected specimen showed POS with areas of de-differentiation composed of high-grade telangiectatic osteosarcoma with associated secondary aneurysmal bone cyst change.
- Parosteal osteosarcoma
- Telangiectatic osteosarcoma