Cysts detected by prenatal ultrasound: an introduction to classification

  Let’s first look at the nature of these cysts: 1. In the pelvis, if it is a girl, it is likely to be an ovarian cyst and 10% is an ovarian cystic teratoma. The latter are mostly benign. Ovarian cysts are very common in newborns and most disappear on their own. The literature mostly recommends conservative observation, exceptions that require surgery include: ovarian cysts with painful torsion. Cysts larger than 5 cm in diameter, as they are more likely to twist and also affect the blood flow to the ovary. Cysts with solid components, i.e., cystic teratomas.  2. Cysts next to the intestine, commonly known as intestinal duplication malformations, mesenteric cysts, lymphangiomas, and large omental cysts, are benign cysts with a good prognosis. Intestinal duplication malformations mostly occur near the ileocecal region and nowadays most of them can be removed by minimally invasive methods.  3. Cysts found under the liver may be cystic biliary atresia or common bile duct cysts.  4. There are many “cysts” in the kidney, which may be hydronephrosis or a true cyst. Multicystic dysplastic kidney (MCDK) is a benign disease in which one kidney is underdeveloped, but if the other side is normal, life is normal. In contrast, polycystic kidney (MCDK) is a genetic disease with two types, which affects both kidneys and can lead to kidney failure after some years.  The most common ones in the chest are congenital cystic adenomatoid malformation (congenital cystic malformation) and bronchogenic cyst. Both are benign cysts, which can be operated electively after birth, and there is a high risk of infection if surgery is not done.  6. Most of the cysts in the neck or are lymphangioleiomas, which are benign. It can be dealt with after the birth of the child.  In summary, almost all cysts detected by prenatal ultrasound are benign. The pediatric surgeon should be consulted for prognosis and treatment options to continue the pregnancy.