Myositis Ossificans



Myositis Ossificans


Elizabeth A. Montgomery, MD









Myositis ossificans is characterized by a zoned proliferation of myofibroblasts with a peripheral rim of woven bone image. This example has a highly cellular central portion image.






The cytologic features of myositis ossificans are similar to those of nodular fasciitis. The lesional cells are uniform and have bland nuclear features. Mitoses can be present but are not atypical.


TERMINOLOGY


Synonyms



  • Fibroosseous pseudotumor of digits (for finger lesions)


  • Pseudomalignant osseous tumor of soft tissue


Definitions



  • Localized self-limited benign lesions composed of cellular myofibroblastic proliferation with ossification


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Rare


  • Age



    • Mean age: ˜ 30 years



      • Range: 1-95 years


  • Gender



    • M > F (˜ 3:2) for classic lesions


    • F > M for digital lesions


Presentation



  • Arise in areas prone to local trauma



    • Elbow, thigh, buttock, shoulder


  • Rapidly growing, variably tender mass

Jul 9, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Myositis Ossificans
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