Presentation
Left upper medial leg swelling.
Patient Data
Age: 15 years
Gender: Male
From the case:
Paraosteal osteosarcoma
{"current_user":null,"step_through_annotations":true,"access":{"can_edit":false,"can_download":true,"can_toggle_annotations":true,"can_feature":false,"can_pin":false},"extraPropsURL":"/studies/130367/annotated_viewer_json?iframe=true\u0026lang=us"}
A large cauliflower-like mass is projecting from the anteromedial cortex of the proximal tibial metaphysics. It elicits low signal on T1 and T2 WI with heterogenous post-contrast enhancement. Adjacent cortical thickening and sclerosis are noted.
From the case:
Paraosteal osteosarcoma
{"current_user":null,"step_through_annotations":true,"access":{"can_edit":false,"can_download":true,"can_toggle_annotations":true,"can_feature":false,"can_pin":false},"extraPropsURL":"/studies/130368/annotated_viewer_json?iframe=true\u0026lang=us"}
on CT, the lesion appears densely calcific with adjacent cortical sclerosis.
Case Discussion
The diagnosis was confirmed by biopsy.
Parosteal osteosarcoma is a subtype of osteosarcoma and arises from the outer layer of the periosteum.
The diagnosis of parosteal osteosarcomas is based on a combination of typical histological and radiographic features