"Is a cyst a tumor?" Many people may unconsciously ask this question. Cysts may grow in all organs of the body, but the vast majority of cysts are benign and asymptomatic, like small blisters in the body. During physical examination, there are three common types of cysts. Simple liver cysts are common in the right lobe of the liver. For asymptomatic liver cysts with a diameter less than 4 centimeters, there is no need to worry too much. Regular follow-up examinations are sufficient. Symptomatic patients may present with abdominal pain, bloating, abdominal masses, decreased appetite, and fever, often indicating the possibility of rapid cyst growth, concurrent bleeding, or infection. It is necessary to seek medical attention at a specialized hospital. Renal cyst is a common kidney disease, divided into simple renal cyst and complex renal cyst. Simple renal cysts are single, multiple or bilateral. The incidence rate increases with age, and most of them are benign. Similar to liver cysts, asymptomatic kidney cysts with a diameter less than 4 centimeters and without affecting renal function do not require treatment and can be reviewed regularly. When a small number of simple renal cysts are combined with rupture or infection, symptoms such as lower back pain, hematuria, and hypertension may occur. In this case, timely medical attention is needed. Complex renal cysts include hemorrhagic cysts, infectious cysts, septal cysts, calcific cysts, etc., which have a certain malignant risk and require further diagnosis and evaluation. Ovarian cysts are divided into physiological cysts and pathological cysts. Physiological ovarian cysts are mostly related to the menstrual cycle, such as corpus luteum cysts and follicular cysts, which develop from the corpus luteum and follicles. For women of childbearing age, ovarian cysts that fluctuate in size during the second half of the menstrual cycle are most likely physiological, and regular follow-up is sufficient. Pathological ovarian cysts are not related to the menstrual cycle and often persist. They are generally classified as benign and malignant, and further diagnosis is needed. During the follow-up period of ovarian cysts, if symptoms such as persistent lower abdominal pain, nausea and vomiting occur, it is important to be alert to torsion or rupture of the ovarian cyst pedicle. At this time, timely medical attention should be sought at the gynecology department to avoid delaying the condition. Which cysts require special attention? In addition to the three types of cysts mentioned above, thyroid cysts, breast cysts, epidermoid cysts, and tenosynovial cysts are also common. Generally, benign cysts have the following four characteristics: regular shape, often circular or elliptical in shape. Clear boundaries. The capsule is intact, with a thin and smooth wall. Ultrasound indicates uniform low echo or no echo, while CT indicates uniform low density. If there are other special labeled words in the physical examination report, such as "visible separation", "thickened cyst wall", "unsmooth inner wall", etc., it indicates that "the cyst is not simple" and may be a cystadenoma, cystadenocarcinoma, hydatid cyst, complex cyst, etc. Further examination is needed to clarify the diagnosis. (Lai Xin She)