Elastofibroma

Elastofibroma is a slowly growing reactive process that is thought to result from friction between the scapula and chest wall. The lesion arises from periosteal fibroblasts, and is found in up to 25% of autopsies in patients older than 55. On CT, however, elastofibromas are seen in only 2% of patients, a difference thought to result from the small size of lesions reported on the autopsy series. The majority are asymptomatic. The overwhelming majority (99%) occur between the chest wall and inferior scapular tip and up to 66% are bilateral.

On CT, elastofibroma appears as a poorly defined, crescent-shaped, heterogeneous soft tissue mass with that has the same attenuation as muscle and contains linear fat-attenuation streaks. On MRI, the lesion is isointense to skeletal muscle and contains streaks that are isointense to fat. Elastofibromas have also been reported to have homogeneous attenuation and signal intensity without visible foci of fat. Other atypical imaging features include bone destruction and intense contrast enhancement, and should prompt further investigation to exclude neoplasm (liposarcoma or metastatic disease, for example).

Reference

• Kransdorf MJ, Meis JM, Montgomery E. Elastofibroma: MR and CT appearance with radiologic-pathologic correlation. AJR Am J Roentgenol. 1992 Sep;159(3):575-9.
• Ochsner JE, Sewall SA, Brooks GN, Agni R. Best cases from the AFIP: Elastofibroma dorsi. Radiographics. 2006 Nov-Dec;26(6):1873-6.