Combining contrast-enhanced ultrasonography (US) with unenhanced US can improve the differential diagnosis of small nonpalpable testicular lesions, according to a study published online June 26 in Radiology.

Extensive use of high-frequency testicular US, for a variety of reasons that include work-up for infertility, has increased the incidental detection of small, asymptomatic, nonpalpable masses, explained Andrea M. Isidori, MD, PhD, of Sapienza University of Rome, and colleagues. Until recently, most intratesticular masses were treated with radical orchiectomy, or removal of the testicles, but US could help distinguish between small malignant tumors requiring orchiectomy and benign lesions that could be recommended for conservative resection or active surveillance.

“The ability to differentiate benign from malignant nonpalpable lesions could enable the use of conservative surgery in selected cases, avoiding the need for repeated expensive procedures,” wrote Isidori and colleagues.

To evaluate the diagnostic accuracy of US, both unenhanced and quantitative contrast-enhanced, the researchers enrolled 115 consecutive patients, median age 34 years old, with nonpalpable testicular lesions between 2006 and 2012. All patients underwent unenhanced scrotal US, contrast-enhanced US, surgical enucleation and a minimum of 18 months of follow-up.

Isidori and colleagues reported that all lesions were 1.5 cm or smaller, with 38 percent being malignant tumors, 37 percent being benign tumors and 25 percent being non-neoplastic lesions.

Results indicated that the features at unenhanced US that enabled the best differentiation of tumors versus non-neoplastic lesions and benign versus malignant tumors were parenchymal microlithiasis, irregular margins and internal vascularization.

For contrast-enhanced US, Isidori and colleagues noted that malignant lesions have distinctive tissue perfusion dynamics involving rapid wash-in and fast washout.

“The combination of unenhanced and quantitative contrast-enhanced US achieves a sensitivity of 82 percent and a specificity of 91 percent in the differential diagnosis of small benign versus malignant tumors,” wrote the authors.