Intramuscular myxoma

Case contributed by Utkarsh Kabra


Swelling in the lateral aspect of left arm.

Patient Data

Age: 35 years
Gender: Female

Note: This case has been tagged as "legacy" as it no longer meets image preparation and/or other case publication guidelines.



Well defined lesion within the intramuscular plane of distal deltoid muscle appearing homogeneously isointense on T1 and hyperintense on T2W / STIR images relative to the surrounding muscle. A subtle rim of fat is seen on T1 images.




Histopath shows oval and spindle shaped cells in a background of myxomatous tissue.

Case Discussion

Intramuscular myxomas are rare benign myxoid lesions, commonly seen in middle-aged women.

On imaging, they are often seen in the large muscles of the thighs, buttocks, or shoulder girdle, and present as well-defined cystic-like lesions with a surrounding rim of fat. They tend to occur in adults around 40 and 60 years with a recognized female predilection (70%). They are associated with fibrous dysplasia as part of Mazabraud syndrome. Our case shows a well-defined homogeneous mass appearing hyperintense on T2W / STIR images and isointense on T1W images relative to surrounding muscle, with a subtle rim of fat. Imaging features, location of the lesion, age group and sex lead to the diagnosis of intramuscular myxoma, which was later confirmed on FNAC.

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.