Comparing Ultrasound with Magnetic Resonance Imaging in the Evaluation of Subungual Glomus Tumors and Subungual Myxoid Cysts.

Introduction: Subungual myxoid cysts and subungual glomus tumors demonstrate characteristic features on magnetic resonance imaging (MRI) and ultrasound (US). It is not yet well-established whether US is congruent to MRI in diagnostic evaluation of these subungual lesions.

Methods: Participants with clinical suspicion for subungual glomus tumors or subungual myxoid cysts were recruited. After clinical evaluation, participants underwent radiography, MRI, and US plus biopsy, aspiration, or excision where possible. Differential diagnoses were revised after review of imaging, and imaging findings were compared to definitive diagnosis by pathology, aspiration, or clinical course.

Results: All lesions were visible on both US and MRI and size estimates agreed between the two modalities. US and MRI findings of subungual glomus tumors and subungual myxoid cysts agreed with their known respective imaging characteristics.

Conclusions: Diagnosis of subungual myxoid cysts and subungual glomus tumors agreed between US and MRI. We provide sample MRI and US imaging parameters for optimal evaluation of subungual myxoid cysts and glomus tumors. We demonstrate that subungual MRI evaluation can be performed without special equipment, allowing for evaluation by most radiology departments. Lastly, US is user-dependent and may be non-inferior for a sonographer familiar with subungual US.