MUCOID DEGENERATION: What it looks like:
There is a lot written about acetabular labral tears but there are other abnormalities of the labrum that can be precursors to or associated with tears. In this 3 part series we will look at Mucoid Degeneration, Labral Dysplasia and Labral Ossification.
The MRI findings are T2/PD hyper-intensity and enlargement of the labrum which can be focal or diffuse. We see it more often in the anterosuperior and superolateral labrum The MRI changes are similar to mucoid degeneration of other structures like the ACL or degeneration that can occur in a discoid meniscus. Mucoid degeneration can occur in an otherwise normal labrum or in dysplastic labrums associated with acetabular dysplasia.
Mucoid degeneration of the acetabular labrum is not uncommon, but Ive not been able to find too much written about it apart from passing reference to it in articles dealing with the labrum (If anyone reading knows of a good article on this, please let me know the link to the article). Here is what it looks like.
Image Above: PD and PDFS scans. Enlargement and diffuse hyperintensity superolateral labrum ( yellow arrow). Signal intensity is high but not as high as fluid.
Image above: PDFS all same patient: Early cystic change ( yellow arrow) within mucoid degeneration. More posterior image demonstrates mucoid degeneration (blue arrows) without cystic change where the signal is increased but not approximating fluid signal.
Image above: PDFS: Areas of hyper-intensity ( yellow arrow) approximating fluid signal suggesting early cyst formation.
Image above all from the same patient: First image (red arrow) early changes of mucoid degeneration with slight increased signal. Second image (yellow arrow) more pronounced changes. Third image (blue arrow) associated labral tear at margins of mucoid degeneration.
Image above: PD, Radial scan. Localized progressive increase in mucoid degeneration anterior labrum (yellow arrow) and a completely normal posterior labrum (blue arrow).
Image Above: Generalized cystic mucoid degeneration (yellow arrows). Only the postero inferior labrum was spared (not shown). Green lines in 2nd image reflect the level of the first image axial scan. Blue arrow first image is a paralabral cyst from a labral tear.
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