Recently, we have received many inquiries from patients and found that misdiagnosis and mistreatment of kidney cysts are not uncommon, so we have written an article to introduce the problems related to kidney cysts. In fact, there are many diseases that cause kidney cysts, most of them are benign, and a few are malignant. Only a few of them are polycystic kidney. 1, isolated kidney cysts: the most common clinical, the kidney only individual cysts, the best prognosis, but the cause is difficult to determine, partly caused by the past had kidney stones blocking the exit of the renal calyces, usually only need to observe, only when greater than 10 cm or infection bleeding need to puncture treatment. The most common causes of stones are hyperuricuria (not necessarily increased blood uric acid, or even decreased blood uric acid), or hypercalciuria, or hyperoxaluria, which can also damage the other kidney and cause kidney damage, among which the main thing is to prevent and control hyperuricuria, insist on daily exercise, do not eat offal, shrimp, crab , asparagus, bamboo shoots, spinach, leeks, broccoli, empty cabbage, and do not drink beer. Be sure to drink more water. 2, multiple renal cysts: clinically common, many causes, often misdiagnosed as polycystic kidney. However, multiple renal cysts generally do not exceed 5 cysts in one kidney, which is the biggest difference with polycystic kidney. This disease needs to be examined to clarify the etiology and to get rid of the cause to prevent and control the progress. Most of them are of unknown etiology and usually only need to be observed, only when they are larger than 10 cm or too superficially located to be easily traumatized, or infected and bleeding, they need to be treated by puncture. There are no effective treatment drugs yet, so don’t be fooled. A few are also the same as the isolated renal cysts described above, caused by stones, which will not be further described here. 3, congenital renal dysplasia: It is often misdiagnosed clinically as polycystic kidney, and this misdiagnosis should not be made because most congenital renal dysplasia is unilateral, although a few patients have both kidneys damaged, but it is generally characterized by significant expansion of renal pelvis and calyces, which is not characteristic of polycystic kidney. 4. Polycystic kidney: a congenital disease, less common than the first three types of cysts, both kidneys have, definitely more than 5 cysts in each kidney, and the cysts are definitely of different sizes, both very large cysts and many very small cysts. They are not characterized by significant dilatation of the renal pelvis and calyces, which is a significant difference from the congenital renal dysplasia described above. The vast majority of polycystic kidneys will enter renal failure uremic syndrome after the age of 50. There is no effective treatment, and although the results of a few physician studies have shown that a low protein diet and RAS system inhibitors can slow its progression, there is a lack of sufficient evidence. 5. Renal tumors presenting as cysts: ultrasound and CT are very easy to identify. If so, treatment by an oncologist is necessary. 6.Familial renal unit consumption: a congenital disease, but it is rare as it does not develop in every family. Most of them show proteinuria and hyponatremia in childhood and are often misdiagnosed as chronic nephritis. ultrasound or CT shows multiple cysts in the kidney, which are easily confused with polycystic kidney, but most of this disease will enter uremia in adolescence and childhood, which means it is more serious than polycystic kidney, which usually enters uremia after the age of 50. 7.Medullary spongy kidney: a congenital disease, rare, ultrasound or CT shows multiple cysts in the medulla of kidney, often misdiagnosed as polycystic kidney. However, really experienced ultrasound doctors can easily see it, and most of them enter uremia in childhood. 8. Renal pelvic lymphatic cysts: when larger, they will compress the collecting system causing obstruction, and in severe cases, they can cause kidney failure and require surgical treatment.