Age / Sex : 15 / F

Age / Sex: 15/F

Chief complaint: Left shoulder pain,

telangiectatic osteosarcoma

Discussion

Findings: Radiographs of the left humerus showed a solitary 2.8 x 5.4 cm sized motheaten osteolytic lesion with a wide zone of transition. A malignant periosteal reaction and cortical destruction were seen in the medial cortex of the proximal humerus. No associated matrix mineralization was seen. MR images showed multilocular cystic lesion with internal multiple fluid levels resulting from hemorrhage. This lesion showed pathologic fracture at medial aspect with periosteal reaction and mild surrounding bone marrow edema. On gadolinium-enhanced images, avid enhancement of the thickened nodular septa were seen.

Differential Diagnosis: Aneurysmal bone cyst, eosinophilic granuloma, classical osteosarcoma

Diagnosis: Telangiectatic osteosarcoma

Discussion:

General

-       a subtype of osteosarcoma: 2.5%–12.0% of all osteosarcomas

-       probably originate from transformed osteoblasts or from stem cells that derive from mesenchymal tissue

Radiographic features

-       Geographic bone destruction

-       A wide zone of transition

-       Endosteal scalloping

-       Marked expansile bone remodeling is common.

-       Osteoid matrix mineralization (only 58% of lesions)

MR features

-       Heterogeneous signal intensity on both T1- and T2-weighted images

-       Fluid levels on T2WI, representing hemorrhage

-       Thickened and often nodular periphery and septa around the hemorrhagic spaces on Gd-enhanced T1WI

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