Soft Tissue Masses: The Underutilization of Sonography

ABSTRACT

For the evaluation of soft tissue masses, sonography (US) has proved to be very accurate in confirming the presence or absence of a lesion, with a very high negative predictive value. Many soft tissue masses result from trauma, inflammation, infection, or cystic changes and are not true neoplasms. In the proper clinical context, US can diagnose a muscular tear, hernia, myositis ossificans, or rhabdomyolysis. Retained foreign bodies are readily identified and localized with US. US differentiates between cellulitis and abscess and can diagnose masses resulting from tendinitis, tenosynovitis, or bursitis. It is the modality of choice for diagnosing cysts, including intact or ruptured Baker's cysts and ganglion cysts in the distal extremities.

Among benign neoplasms, lipomas and hemangiomas display a wide spectrum of echogenicity. US can diagnose nerve sheath tumors by demonstrating the connection between the mass and the normal nerve. Except for some well-differentiated liposarcomas, which may appear echogenic, the vast majority of malignant tumors in the soft tissues are hypoechoic. Real-time US is ideal for guiding large-core needle biopsy of soft tissue sarcomas. US is extremely sensitive in detecting early recurrences after surgical excision, which are readily confirmed by US-guided fine-needle aspiration. Any nonpalpable mass visualized by US can be conveniently localized pre- or intraoperatively with US guidance.

Provided the examination is done by a well-trained operator using state-of-the-art equipment, the cost-effectiveness of US justifies its use as a first-line examination technique in many situations involving soft tissues, with magnetic resonance imaging being the problem-solving tool and staging procedure.

KEYWORDS

Ultrasound, mass - ultrasound, soft tissue - soft tissues, trauma - soft tissues, inflammation - soft tissues, neoplasms - soft tissues, sarcomas - soft tissues, cysts