A mother brought her several-month-old baby to the doctor with tears in her eyes. The baby had a cyst in one testicle (ultrasound confirmed that it was not a syringomyelia outside the testicle). A doctor advocated removing the testicle. Personally, I would suggest that the first step is just to remove the cyst and do pathology tests. There is a small cyst inside a three-quarter cyst in the ultrasound. What is the nature of the cyst and can the ultrasound differentiate the nature of the cyst? The more common causes of testicular cysts in infants and children are teratomas and epithelioid cysts. Other rare ones include dermatomal cysts, lymphadenomas, testicular cysts, testicular cystadenoma, and testicular tumors (most of the latter have some solid tumor component). A comparative study of ultrasound epithelioid cysts, benign and immature teratomas published a few months ago (J Ultrasound Med. 2015 Oct;34(10):1745-51.) found that. Overall, more than 80% of the 19 testicular cysts were benign (6 epidermoid cysts and 10 mature teratoma) and more than 10% were neutral immature teratomas (3 cases, immature teratoma, with some malignant potential). Immature teratoma is characterized by the young age of the child (mostly under eight months), elevated alpha fetoprotein (23ng/mL or more), and a tumor length of 2.5 cm or more. The presence or absence of a solid tumor component on ultrasound cannot predict the nature of the teratoma. 100% confirmation of the diagnosis still depends on pathological sections after biopsy. If every child has an orchiectomy, then part of it will be wrongly cut. A missing testicle is a big psychological blow to both the parents and the child. Therefore, only cyst excision should be done with normal meconium, preserving the testis. If the pathology report reveals that it is immature or malignant teratoma, most of the patients’ parents will accept a second orchiectomy.