High-resolution ultrasonography is a more useful primary diagnostic tool than magnetic resonance imaging for subungual glomus tumors: a single-center retrospective study

Purpose: Ultrasonography (US) and magnetic resonance imaging (MRI), which has better resolution, have been suggested as appropriate diagnostic tools for digits; however, comparative studies of both modalities are scarce. This study compared the diagnostic performance of high-resolution US and MRI in characterizing subungual glomus tumors. Methods: We retrospectively analyzed the data of consecutive patients who were examined with high-resolution US and MRI before surgical exploration for subungual tumors from January 2017 to April 2020. The patients’ clinical data and radiological findings were collected. Historical reports for diagnostic confirmation and measurements of mass size were reviewed. We conducted the McNemar test and evaluated the degree of agreement between the size measurements made using both techniques.Results: Overall, 22 patients (age range, 19–72 years) underwent surgical exploration and had subungual glomus tumors. The mean duration from initial symptom presentation to diagnosis was 7 years (range, 5–30) years. Only nine patients (40.9%) presented with the symptomatic triad of pain, cold sensitivity, and tenderness. MRI detected lesions in 19 cases (86.4%); three cases (13.6%) were undetected. Contrastingly, US was able to detect all lesions. Nine patients (40.9%) had visibly rich blood flow in tumor tissues on Doppler US. MRI and US showed bone erosion in eight and 15 cases, respectively. Conclusion: The detection rate of high-resolution US for subungual glomus tumors was as high as that of MRI. US can be applied easily and quickly and can be more useful as a primary diagnostic tool.