Clinically unsuspected foreign bodies: the importance of sonography.

OBJECTIVE: To show the value of sonography in the detection of clinically unsuspected foreign bodies appearing as soft tissue masses. METHODS: High-resolution B-mode and color Doppler sonography was performed in 288 patients referred with superficial soft tissue masses over a period of 2 years. RESULTS: In 8 lesions in 6 patients, sonography showed small curved or linear echogenic structures surrounded by hypoechoic masses characteristic of foreign bodies with granulation tissue. One lesion had increased vascularity on color Doppler sonography. Patients were referred for other imaging studies, including magnetic resonance imaging, computed tomography, and bone and labeled red blood cell scintigraphy, which did not add relevant information. Three patients underwent surgery; foreign bodies were found in 2, and infected granulation tissue was found in 1. Spontaneous resolutions and no growth of the lesions were seen in the other 2 patients. CONCLUSIONS: The possibility of a foreign body should be considered when scanning soft tissue masses even in the absence of a relevant clinical history. Once a foreign body is diagnosed, no further workup is indicated.