82-year-old male with history of right upper back soft tissue swelling/mass which he first noticed approximately 3 weeks ago. No pain, no limited range of motion, no fevers, no redness or any other complaints. Physical exam reveals a fluctuant, nontender soft and relatively mobile approximately 6 to 8-cm wide area of masslike swelling in the right upper back just deep to the skin surface. No overlying redness or crepitus.Ultrasound shows a large, approximately 5-10 cm structure within the subcutaneous soft tissues between the skin and the chest wall. It appears separate from the underlying ribs and chest wall, and has a clearly defined interface with the adjacent soft tissues. The structure contains relatively homogeneously isoechoic material that causes dirty shadowing and partially obscures its posterior extent. Although the relatively high acoustic impedance of this structures internal contents limits evaluation, we favor a benign etiology such as epidermoid inclusion cyst.
Findings suggestive of benign etiology, such as a large epidermoid inclusion cyst.