Introduction to LGFMS Imaging Challenges

Low-grade fibromyxoid sarcoma (LGFMS), also known as Evans tumor, is a rare and often deceptive soft tissue malignancy. Because this tumor typically presents with non-specific features on conventional imaging, clinicians frequently find preoperative diagnosis difficult. A recent case report involving a 57-year-old woman with an axillary mass demonstrates how super-resolution ultrasound can significantly improve the assessment of these lesions. While standard imaging showed an irregular, vascularized hypoechoic mass, advanced techniques provided a deeper look into the tumor’s internal architecture.

The Role of Contrast-Enhanced Ultrasound (CEUS)

Contrast-enhanced ultrasound (CEUS) serves as a critical bridge between conventional sonography and advanced microvascular imaging. In this specific case, CEUS revealed early centripetal hyperenhancement followed by rapid washout. Consequently, these patterns strongly suggested a malignant nature rather than a benign growth. Furthermore, CEUS helps delineate the boundaries of the lesion more clearly than B-mode ultrasound. However, while CEUS is excellent for macrovascular patterns, it often lacks the detail required to visualize the finest vessel structures.

Diagnostic Insights from Super-resolution Ultrasound

The application of super-resolution ultrasound (SR-US) represents a major technological leap in oncological imaging. This technique overcomes the diffraction limit of conventional ultrasound by tracking individual microbubbles to map the microvasculature. In the reported axillary LGFMS case, SR-US successfully identified a highly disorganized microvascular architecture. Specifically, the technology visualized intricate vessel patterns that standard Doppler imaging could not detect. This detailed vascular mapping is essential for surgeons during preoperative planning to understand the tumor's blood supply and potential invasiveness.

Pathological Confirmation and Clinical Outcomes

Following the advanced imaging assessment, the patient underwent surgical resection. Pathological examination subsequently confirmed the diagnosis of low-grade fibromyxoid sarcoma. This case underscores the importance of integrating multi-modal imaging techniques. By combining CEUS and SR-US, medical teams can achieve a more comprehensive understanding of soft tissue tumors before surgery. Therefore, these tools may reduce diagnostic uncertainty and improve the management of rare malignancies like LGFMS.

Frequently Asked Questions

What is the benefit of super-resolution ultrasound over Doppler?

Super-resolution ultrasound provides a much higher spatial resolution by tracking microbubbles. This allows it to visualize microvessels as small as 20–50 micrometers, which is far beyond the capability of conventional Doppler imaging.

How does LGFMS typically appear on standard ultrasound?

On standard B-mode ultrasound, LGFMS often appears as a well-defined or slightly irregular hypoechoic mass. However, these features are non-specific and can overlap with benign lesions like fibromas or lipomas.

Is super-resolution ultrasound widely available in clinical practice?

While SR-US is an emerging technology, its availability is increasing in specialized imaging centers and research hospitals. It is primarily used for complex diagnostic cases where detailed vascular mapping is required.

Disclaimer: This content is for informational and educational purposes only and does not constitute medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider regarding any medical condition. Refer to the latest local and national guidelines for clinical practice.

References

Zhao X et al. Application of super-resolution ultrasound in preoperative assessment of axillary low-grade fibromyxoid sarcoma: a case report. J Ultrasound. 2026 May 03. doi: 10.1007/s40477-026-01133-z. PMID: 42070221.

Koh SH et al. Low-grade Fibromyxoid Sarcoma: Ultrasound and Magnetic Resonance Findings in Two Cases. Skeletal Radiol. 2005 Sep;34(9):550-4.

Couture O et al. Ultrasound localization microscopy and super-resolution: A review of the first decade. IEEE Trans Ultrason Ferroelectr Freq Control. 2018 Aug;65(8):1304-1320.