Purpose or Case Report: The purpose of this educational presentation is to demonstrate ultrasound technique and characteristic sonographic findings of common superficial pediatric extremity soft tissue lesions. We also offer advice on how to differentiate benign from malignant lestions. Children frequently present with unexplained “lumps and bumps” on their extremities. These lesions are often invisible on radiography; MRI might require use of sedation; and CT exposes the child to radiation and often requires iodinated contrast. Ultrasound (US) is a cost-effective, radiation-free, and dynamic method to evaluate superficial soft tissue lesions.

We discuss choice of transducer based on lesion location. We explain why a multifrequency transducer, which allows for the evaluation of both superficial (higher frequency spectrum of the transducer) and deeper (lower frequency spectrum of the transducer) components of the lesion is important. The use of compound imaging is explained, as multiple angles of insonation are combined to provide a more complete image of the structure being interrogated. For lesions involving the hands or feet, we explain the water-bath technique. Water is an excellent medium for ultrasound waves and will minimize artifacts from air and inadequate surface contact that plague evaluation of the distal extremities.

We then discuss characteristic sonographic appearance of the following conditions: vascular anomalies, osteomyelitis and subperiosteal abscess, hematoma, subcutaneous granuloma annulare, Pilomatricoma, lipoma, ganglion and Baker cyst, muscle hernia, osteochondroma, foreign bodies, and malignant conditions.
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