Telangiectatic osteosarcomas (TOS) are an uncommon variant of osteosarcoma that represent 2.5-12% of all osteosarcomas.
TOS have similar demographics to that of conventional osteosarcoma and typically presents in adolescents and young adults (reported age range of 3-67 years with a mean age of 20 years). There is a recognised male predilection.
Most osteosarcomas have a small telangiectatic component but in order to classify as a telangiectatic osteosarcoma the telangiectatic component should comprise >90% 1.
Most of the tumour comprises of large blood filled spaces separated by thin bony septations.
Microscopically the tumour consist of vascular sinusoids surrounded by thin septae, osteoid matrix and cells with significant pleomorphism and high mitotic rate.
Most common locations by site are:
- around knee:
- femur: 50-62%
- tibia: 10-25%
- humerus: 12-16%
In terms of location within bone:
- metaphyseal: ~80%
- diaphyseal: ~20%
Typically seen as an expansile lytic bone lesion at the metaphysis:
- geographic bony destruction with wide zone of transition tends to be more common than permeative bony destruction 6
- less osteoid matrix than conventional type
- pathological fractures are frequent
- low attenuating fluid-fluid levels within the lesion (in ~80% of cases)
- useful at assessing associated cortical destruction
- thick peripheral and nodular septal enhancement
- osteoid matrix mineralisation
- commonly shows fluid-fluid levels within the lesion (~90% of cases) with variable signal intensity
- allows appreciation of surrounding soft tissue components
- signal characteristics are often heterogeneous
- enhancement of septations as well as the soft tissue component may be observed
- haemorrhage appears as hyperintense on T1 and variable signal intensity on T2
Treatment and prognosis
The treatment of telangiectatic osteosarcoma is often similar to that of conventional osteosarcoma: chemotherapy followed by wide surgical resection and limb salvage or amputation.
Survival rate of telangiectatic osteosarcoma (estimated at ~70%) is similar to that of conventional osteosarcoma.
They are associated with a high rate of pathological fractures 4.
Considerations on plain film include:
- aneurysmal bone cyst (ABC): should not have any soft tissue component outside the lesion
- giant cell tumour of bone: again no soft tissue component
- osteolytic metastatic bone lesions: should not have any fluid levels
History and etymology
First described by J Paget in 1854 7.
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