Learning objectives
Review the imaging findings in a case series of primary and secondary lipoma aborescens
Understand the underlying pathophysiology
Review the underlying associations in secondary lipoma aborescens
Background
Lipoma aborescens is a villous proliferation of the synovium whereby the subsynovial connective tissue is replaced by mature fat cells,
occuring most commonly in the suprapatellar pouch (Fig 1).
Other more unusual sites have however been described,
as demonstrated in this pictorial review.
Whilst a degree of subsynovial fatty infiltration is not an uncommon finding particularly in elderly patients,
more widespread fatty change is needed for the diagnosis.
In extensive disease,
the condition can be mistaken for tumour.
Lipoma aborescens is however thought to be...
Imaging findings OR Procedure Details
We review a series of 15 cases of lipoma aborescens in multiple sites including the knee (Fig 1-4) and more unusual locations such as the hip (Fig 5) and cubital bursa (Fig 6-8).
The spectrum of imaging findings includes mass-like proliferation of the knee,
which can be mistaken for tumour. It is important to look for underlying conditions such as gout (Fig 9-10),
rheumatoid arthritis and osteoarthritis (Fig 3).
The differential diagnosis includes synovial chondromatosis,
pigmented villonodular synovitis (PVNS),
rice bodies (in rheumatoid arthritis),
venous...
Conclusion
Lipoma aborescens is an increasingly recognised intra-articular process,
and an in depth understanding of the imaging features and underlying pathophysiology is therefore of benefit.
References
1.
Murphey MD,
Carroll JF,
Flemming DJ,
Pope TL,
Gannon FH,
Kransdorf MJ.
From the archives of the AFIP: benign musculoskeletal lipomatous lesions.
Radiographics 2004 Sep-Oct;24(5):1433-66
2.Sanamandra SK,
Ong KO.
Lipoma arborescens.
Singapore Med J.
2015;55 (1): 5-10.