Parosteal osteosarcoma

120 views535y Female10/9/2026

Clinical Presentation

Mass in the distal right thigh

1Exophytic and cauliflower-like mass with dense osteoid matrix arising from the posterior lateral aspect of the distal femoral metaphysis
2On the lateral view, a thin lucent line is noted separating the bulky mass from the adjacent cortex
3The radiographic findings are highly suggestive of juxtacortical osteosarcoma
4parosteal type
5No pathological fracture seen
6The CT study demonstrates the morphology of the tumor and the epicenter of the mass at the posterolateral distal femoral metaphysis with no invasion to the medulla
7There are areas of low attenuation seen peripherally within the mass which may represent chondroid tissue
8On MRI, the mass demonstrate heterogeneous low to intermediate signal intensity on T1, T2 fat-suppressed and STIR sequences with a heterogeneous pattern of enhancement on post-contrast images.These features are likely explained by internal dense calcifications
9Perilesional oedema is noted
10No intramedullary involvement or skip lesions.