We describe the case of a 78-year-old man with a large elastofibroma deep to his scapula that was inconspicuous on MRI examination with his arm at his side in neutral position. The mass was not detected sonographically until the patient abducted his arm, allowing the elastofibroma to emerge from under the scapula. The diagnosis of elastofibroma was suggested by the typical sonographic appearance of a hypoechoic mass with interspersed linear echogenicity, resembling muscle. The mass was excised, and the diagnosis was confirmed on histopathologic examination.
