Intramuscular Brachialis Lipoma
Patient was seen in surgery and opted for conservative therapy. He did not want a biopsy.
If size increases or pain worsens, he will undergo biopsy.
Physical therapy for his shoulder helped improve strength and decrease pain.
Strength is near normal.
Pain is now resolved.
He is currently able to do all activities, including fly fishing.
Lipomas occur in about 1% of the population and are usually benign, depending on the location. If a fatty tumor is located in the retroperitoneum or is intramuscular, it should be considered to be a potential liposarcoma until proven otherwise. Liposarcomas are malignant tumors that arise from adipocytes. They may recur locally and have potential to metastasize.
There is suggestion that trauma-related fat herniation through tissue planes creates so-called pseudolipomas. There is also a theory that trauma-induced cytokine release triggers pre-adipocyte differentiation and maturation. So far there is no definitive link between trauma and lipoma formation.
On clinical exam, intramuscular lipomas cause a diffuse, palpable swelling, which is more prominent when the related muscle is contracted. MRI does not allow an absolute, reliable distinction between a lipoma and a liposarcoma. This is why biopsy is suggested for a definitive diagnosis.
Nickloes, T. Lipomas. Medscape. 3 Jun 2013. Editor: Geibel, J. Accessed on 9 Aug 2014.
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