Elastofibroma, an ill-defined fibroelastic tumor-like condition made up of enlarged and irregular elastic fibers.
It is a slow growing, deep-seated, firm mass, often presenting bilaterally.
It develops specifically in the subscapular or infrascapular area, deep to the muscle, sometimes even attached to periosteum of ribs.
It is usually located between the shoulder blade and the lower neck, with rare tumors reported in the chest wall.
This is a very rare phenomenon making up less than 0.001% of soft tissue tumors.
It usually presenting in elderly patients and more commonly so in women than men (5:1).
Rarely, there may be pain or tenderness, but this is rare.
Genetic predisposition, occurs with alterations of short arm of chromosome 1, and may suggest systemic enzymatic defect.
Repeated trauma or friction seems unlikely.
CT shows a poorly circumscribed, heterogeneous soft tissue mass, with a signal intensity similar to skeletal muscle.
US indicates elastofibromas are deep to the musculature as a multilayered pattern of hypoechoic linear areas of fat deposition intermixed with echogenic fibroelastic tissue.
The mass often protrudes from the subscapular region upon shoulder abduction.
It is an ill defined, nonencapsulated, rubbery, firm, white lesion with interspersed fat.
Most lesions are around 5 cm, but can be up to 20 cm.
Histologically, there is heavy dense areas of collagenous tissue intercepted by fat an abnormal elastic fibers.
The elastic fibers are course, thick, darkly eosinophilic, frequently fragmented and easily identified.
The elastic fibers will be highlighted histologicallyn by elastic stains.
Differential diagnoses include:
a spindle cell lipoma, fibroma and fibromatosis colli.
Excision is the treatment of choice.
Bleeding into the space can be a potential complication.
It has no malignant potential.
Possibly more cases in Okinawa.