Telangiectatic osteosarcoma

 

We will discuss a case of telangiectatic osteosarcoma, including imaging findings with differential diagnosis.

16-year-old man presented with complaints of left upper arm swelling for 1 year.

Xray left shoulder was performed which shows ill-defined lesion with osteoid matrix (orange arrow) causing geographic lytic destruction of proximal meta-diaphysis of left humerus with a wide zone of transition, spiculated or sunburst (blue arrow) and Codman type of periosteal reactions in its inferior aspect (yellow arrow).

Subsequent MRI left shoulder was performed, coronal T2W images shows a large relatively well-defined lobulated heterogeneously enhancing solid cystic mass in proximal meta-diaphyseal region of left humerus causing cortical destruction of head, neck, and proximal shaft. Cystic component of the mass shows multiple locules and enhancing thick intervening septae within. On GRE MEDIC images, the locules shows blood fluid levels within.

This was a proven case of telangiectatic variety of osteosarcoma.

Telangiectatic osteosarcoma is a subtype of osteosarcoma consists of large haemorrhagic or necrotic cavities. It occurs in the medullary cavity in the metaphyseal region of long bones. Most frequently affected site for these tumors is the distal femur and proximal humerus. The classic radiographic appearance of telangiectatic osteosarcoma is a lesion with geographic bone destruction, a wide zone of transition, endosteal scalloping and osteoid type of matrix mineralisation.

Important differential of fluid-fluid levels containing bone lesions are:

·         Aneurysmal bone cyst (ABC)

·         Telangiectatic variety of osteosarcoma

·         Simple bone cyst (after fracture)

The main differential diagnosis for telangiectatic osteosarcoma is an aneurysmal bone cyst. The distinction between the two conditions is usually made with MR imaging.

·         ABCs shows thin enhancing peripheral septa (usually 2–3 mm thick) whereas in telangiectatic osteosarcoma, the periphery and septa around the haemorrhagic spaces are thickened and often nodular and enhance with contrast.

·         At CT, the presence of an osteoid matrix within nodular or septal regions (intraosseous or soft-tissue component) is a feature of telangiectatic osteosarcoma

·         Telangiectatic osteosarcomas are associated with aggressive growth features such as cortical destruction and extension into the surrounding soft tissues. In contrast, ABCs cause marked expansile remodelling of bone and cortical thinning but lack true soft-tissue involvement.