Imaging of Pediatric Testicular and Para-Testicular Tumors: A Pictural Review

SIMPLE SUMMARY: Pediatric testicular tumors are rare and represent 1% to 2% of all solid tumors in children. Germ-cell tumors are the most frequent etiology; most are benign in the pre-pubertal population, whereas post-pubertal testicular tumors are similar to those that occur in adults, with potential malignancy. The development of testis-sparing surgery for presumed benign lesions enhances the need for better pre-operative tumor characterization by imaging, among other tools. Ultrasonography (US) remains the first-line examination for scrotal pathology assessment, but other techniques such as contrast-enhanced US, elastography, or scrotal MRI are emerging modalities for scrotal evaluation both in children and adults. This review provides an overview of imaging features of the most frequent testicular and para-testicular tumor types in children and discusses the role of imaging in disease staging and monitoring children with testicular tumors or risk factors for testicular tumors. ABSTRACT: Pre- and post-pubertal testicular tumors are two distinct entities in terms of epidemiology, diagnosis and treatment. Most pre-pubertal tumors are benign; the most frequent are teratomas, and the most common malignant tumors are yolk-sac tumors. Post-pubertal tumors are similar to those found in adults and are more likely to be malignant. Imaging plays a pivotal role in the diagnosis, staging and follow-up. The appearance on ultrasonography (US) is especially helpful to differentiate benign lesions that could be candidates for testis-sparing surgery from malignant ones that require radical orchidectomy. Some specific imaging patterns are described for benign lesions: epidermoid cysts, mature cystic teratomas and Leydig-cell tumors. Benign tumors tend to be well-circumscribed, with decreased Doppler flow on US, but malignancy should be suspected when US shows an inhomogeneous, not-well-described lesion with internal blood flow. Imaging features should always be interpreted in combination with clinical and biological data including serum levels of tumor markers and even intra-operative frozen sections in case of conservative surgery to raise any concerns of malignity. This review provides an overview of imaging features of the most frequent testicular and para-testicular tumor types in children and the value of imaging in disease staging and monitoring children with testicular tumors or risk factors for testicular tumors.