A mother brought her several-month-old baby to the doctor with tears in her eyes. There was a cyst in one of the baby’s testicles (ultrasound confirmed that it was not a syringomyelia outside the testicle). Some doctors advocate having the testicle removed. Personally, I would recommend just removing the cyst as a first step and doing pathology. Here are the literature references and the logic of my recommendation. I looked at the ultrasound and there is a small cyst inside a three centimeter cyst. What is its nature? 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, immature teratoma, with some malignant potential). Immature teratoma is characterized by the young age of the child (mostly under 8 months), elevated alpha fetoprotein (23 ng/mL or more), and a tumor length of 2.5 cm or more. The presence of a solid tumor component on ultrasound is not predictive of the nature of the teratoma. 100% confirmation of the diagnosis still depends on pathological sections after biopsy. If every child has an orchiectomy, some of them will be wrongly cut. One missing testicle is a big psychological blow to both the parents and the child. Therefore, I personally would only do a cystectomy and keep the testicle if the meconium is normal. If the pathology report reveals an immature or malignant teratoma, most parents will undergo a second orchiectomy.