Learning objectives
To illustrate the radiographic CT and MRI and Nuclear Imaging features of ABC.
The differential Diagnosis of ABC and lesions with Blood fluid levels are discussed.
ABC and its Close Mimic -The TOS (Telenegeictatic OS) are differentiated and the pearls and Pitfalls are illustrated.
Background
Expansile of lesion of bone containing thin walled blood filled cavities
.Types: Primary ABC (65-99%): may be related trauma or circulatory defect
Secondary ABC (1-35%):arises in a pre existing bone tumor causing venous obstruction or AV fistula
Intra osseous ABC: Primary cystic telengiectatic tumor of Giant cell family in the bone marrow cavity with slow expansion of the cortex,
rarely trauma related.
Extra osseous ABC: Post traumatic haemorrhagic cyst –originates in surface erodes through the cortex in to Marrow
Sites;Soine 12-30% with predilection for posterior...
Findings and procedure details
Radiographs: purely lytic ,eccentric radiolucent ,aggressive expansile ballooning with soap bubble pattern,
internal trabeculae,rapid progression,
no peri osteal reaction ,Buttresssing with reaction when there is a cortical break,
Almost invisible Thin cortex,
respect epiphysis with no sub articular extension unlike GCT
CT : Blood filled sponge with fluid fluid haematocrit levels Due to sedimentation.
MRI: Cystic; heterogeneous signal intensities on T1 and T2 due to different stages of blood by products like Deoxy Hemoglobin Met hemoglobin etc.
with fluid fluid haematocrit levels ;low signal intensity...
Conclusion
This exhibit shows the Common and Uncommon Avatars of ABC with Differential diagnosis
References
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et al: Diagnosing...