OBJECTIVE The purpose of this pictorial essay is to review the sonographic and pathologic appearances of the most common solid and complex extratesticular masses in children. CONCLUSIONS Solid or complex extratesticular masses, especially those that are rapidly growing and are painless, raise concerns regarding malignant rhabdomyosarcoma. Mimickers of rhabdomyosarcoma include inflammatory processes such as pseudotumor, chronic epididymitis, or meconium periorchitis. Because sonography cannot distinguish benign from malignant, worrisome extratesticular masses should be biopsied or removed.