The incidence of testicular tumors in children is only 0.5– 2.0 per 100 000 and it is less in the neonatal period. Testicular tumors are classified as germ cell tumors or non–germ cell tumors. Germ cell tumors are further classified as seminomas and non-seminomatous tumors. Seminomas are the most common testicular tumors among adults. Whereas, non-seminomatous germ cell tumors are the most common testicular tumors among children and include teratomas, yolk sac tumors, and embryonal carcinomas. Non–germ cell tumors include Sertoli and Leydig cell tumors and are rare in children [5]. Testicular teratomas are the most frequent histologic type in children and are responsible for approximately 50% of prepubertal tumors. Histologically, prepubertal teratomas can consist of any combination of the three primitive embryological germ-cell layers (ectoderm, mesoderm, and endoderm). These give rise to different tissues (epithelium, cartilage, fat, bone, muscle, and neural elements), which accounts for their heterogeneous appearance on ultrasound with areas of calcification. Teratomas are poorly or mildly vascularised on color Doppler [6]. Teratomas can occur in the neonatal period, although the average age of presentation is 18 months. Yolk sac tumors are the second most common and are most presenting at an age younger than 2 years. The prognosis can be getting better when it occurs during the first year of life [7]. Testicular tumors usually manifest as painless testicular mass in an enlarged scrotum (82–90%), and less than 10% as painful mass secondary to hemorrhage or necrosis. Physical exploration and other clinical data (fever, acute pain, vomiting) can help to differentiate a testicular tumor from hydrocele, inguinal hernia, testicular torsion, or inflammatory scrotum [8]. Mature teratomas may have a cystic quality on palpation and transillumination because of cysts filled with fluid or mucous. These testicular teratomas can be confused with hydroceles, and the diagnosis of a testicular tumor will be confirmed at surgery [9]. Nevertheless, hydroceles can be associated with testicular tumors in 15–50% of cases, and a thorough examination is needed to determine the presence of other associated pathologies, such as testicular torsion, epididymitis, and inguinal hernia [6].

Ultrasonography (US) is the imaging modality of choice for studying testicular tumors, because of its low cost, wide availability, and high sensitivity for detecting lesions. A benign tumor is suggested when ultrasonography shows a mainly cystic component, well-defined borders, or normal to increased echogenicity lesion. A malignant tumor is suspected when ultrasonography shows an inhomogeneous, hypoechoic, not well-circumscribed, or diffuse infiltration lesion. However, these ultrasonographic findings may overlap [4]. Where scrotal US findings are inconclusive or non-diagnostic, Magnetic Resonance Imaging (MRI) can contribute to ascertain the diagnosis [10]. Assessment of tumor markers, including α-fetoprotein (AFP), β-human Chorionic Gonadotropin (β-hCG), and lactate dehydrogenase, is routine and aids not only in diagnosis but also in prognosis and risk stratification. α-Fetoprotein levels are typically much higher in yolk sac tumors than in teratomas. It should be noted that infants younger than 6 months show high AFP levels physiologically, which renders interpretation is more challenging [11]. Testis-Sparing Surgery (TSS) should be used in prepubertal testicular teratomas when the normal testicular tissue seems salvageable in the US and with normal tumor markers. Intraoperative frozen section examination when available can be applied to confirm the pathology of the tumor as well as to justify the conservative surgery [12]. TSS may reduce psychological and cosmetic consequences associated with radical orchiectomy and it may reduce the risk of impaired fertility. Furthermore, in both prepubertal and postpubertal patients with a solitary testis preoperatively, TSS is recommended to preserve Leydig cell function and thereby testosterone production, and to conserve any fertility potential [13]. In the absence of a reassuring frozen section, complete orchiectomy is usually the treatment of choice. In prepubertal patients, metastatic evaluation can be deferred until a histologic diagnosis of the primary tumor has been made. Adjuvant chemotherapy in malignant testicular tumors is required. Postoperative follow-up is highly recommended for these patients with physical examination, scrotal ultrasonography, and tumor markers levels [14].