From the Guidelines
Ultrasound is recommended as the initial imaging modality for evaluating a soft tissue mass when there is clinical suspicion of a superficial lesion. This approach is supported by the most recent and highest quality study, which highlights the effectiveness of ultrasound in assessing soft-tissue masses, particularly for superficial lesions 1. The key benefits of using ultrasound as the initial imaging modality include:
- Its ability to distinguish between cystic and solid lesions
- Assessment of the size and relationship of the lesion to surrounding structures
- Evaluation of vascularity
- Guidance for further management decisions, including the potential for needle biopsy
- It is widely available, cost-effective, and does not use ionizing radiation, making it a preferred first-line imaging tool 1. For deeper masses or when malignancy is suspected based on ultrasound findings, additional imaging with MRI is typically warranted 1. It's also important to note that ultrasound assessment is highly user-dependent, and in cases of diagnostic uncertainty, an MRI of the affected region should be performed 1. Overall, the use of ultrasound as the initial imaging modality for soft tissue masses prioritizes morbidity, mortality, and quality of life by providing a rapid, non-invasive, and cost-effective means of assessing these lesions and guiding further management.
From the Research
Indications for Ultrasound of Soft Tissue Masses
- Masses that are deep to the fascia, are 5 cm in diameter or larger, grow rapidly, or present suddenly without explanation should prompt further workup, including ultrasonography 2
- Ultrasonography can be used to assess size, depth, solid or cystic nature, and associated vasculature of soft tissue masses 2, 3
- Ultrasound is an ideal triaging tool for superficial soft tissue masses, and can readily identify and exclude benign lesions such as superficial lipomas and ganglia 4
Characteristics of Soft Tissue Masses that Require Ultrasound
- Masses with atypical ultrasound features, or those that are deep or large, may require further evaluation with MRI and biopsy 5, 4
- Suspicious soft tissue tumors, such as those with a high risk of malignancy, should be carefully planned by a multidisciplinary team involving specialized surgeons and pathologists at a tumor center 4
- Ultrasound can characterize most soft tissue masses based on their ultrasound appearance alone, but may not be sufficient to distinguish benign from malignant tumors in all cases 5
Practical Approach to Ultrasound of Soft Tissue Masses
- A systematic approach to the ultrasound evaluation of superficial soft-tissue masses can help establish a confident diagnosis, including knowledge of proper technique in image acquisition and characteristic sonographic appearances of common masses 6
- Tips for undertaking MRI examinations, such as tailoring the examination to address specific questions that have not been adequately addressed on ultrasound examination, can be helpful in further characterizing indeterminate masses 5