Synovial hemangiomas are rare benign vascular malformations that occur in relation to the joint. It is sometimes considered a subtype of soft tissue hemangiomas.
The lesions typically present in children and young adults. Occasionally patients can have recurrent haemarthroses .
Patients may have pain, swelling and/or limited joint mobility.
The lesions can be cavernous, capillary or mixed.
Most lesions tend to occur around the knee .
Plain film findings are generally non-specific and may be seen as a soft tissue mass adjacent to the knee. Accompanying phleboliths may be present.
Typically seen as a lobulated intra-articular mass (although the lesions can be either lobulated or diffuse).
Signal characteristics include:
- T1: usually of intermediate signal
- markedly hyperintense background; likely from pooled blood within vascular spaces
- low-signal-intensity linear structures within lesion; likely from fibrous septa or vascular channels
- fluid-fluid levels may be present
- T1 C+: marked enhancement
Imaging differential considerations include: