Sonographic appearances of torsion of the appendix testis and appendix epididymis in children

Purpose: The most common cause of acute scrotum in prepubertal boys is torsion of the testicular or epididymal appendages. The purpose of this retrospective study was to characterize the features of these lesions as viewed on sonographic (US) and color Doppler US examination. Methods: During a 220-week period, 527 male patients 0-17 years old had been referred from the pediatric emergency department for scrotal US evaluation. Torsion of the appendix testis or appendix epididymis had been diagnosed in 19 (3.6%) patients, 3-14 years old (mean, 9.4 years); those patients became our study cohort. The clinical diagnoses in 15 of those patients had been suspected testicular torsion (n=7), trauma (n=4), suspected epididymitis and/or orchitis (n=3), and suspected hydrocele (n=1). The remaining four patients had been referred owing to nonspecific pain. None of the 19 patients had had the "blue-dot sign" on physical examination. Results: In the 19 patients diagnosed with torsion of the intrascrotal appendages, color Doppler US demonstrated a round or oval avascular lesion with heterogeneous echotexture (n=18), posterior enhancement (n=13), and hyperemia of the surrounding structures (n=15). All lesions (appendages) were adjacent (n=16) or in close proximity (n=3) to the upper pole of the testis. Fifteen of the appendages were adjacent to both the testis and the epididymis, four were adjacent to the epididymis alone, and none were adjacent to the testis alone. Owing to the close proximity of the upper pole of the testis, the epididymis, and the appendage, differentiation between testicular and epididymal appendages was not possible. Conclusions: Torsion of the intrascrotal appendages has a typical appearance on color Doppler US; thus, we believe that it is the method of choice for diagnosing torsion of the scrotal appendages and safely ruling out other disorders as well as avoiding unwarranted surgical intervention or antibiotic treatment.