Dermatofibroma are common benign skin tumours that cause lumps in the skin and frequently cause concern upon discovery. The causes of dermatofibroma may include a reaction to trauma such as insect bites but the precise cause is often unclear.
Causes. It's not clear what causes simple kidney cysts. One theory suggests that kidney cysts develop when the surface layer of the kidney weakens and forms a pouch (diverticulum). The pouch then fills with fluid, detaches and develops into a cyst. 1  Symptoms. 2  Risk factors.
Presentation: kidney cysts usually occur before liver cysts and chronic kidney disease is common. However, polycystic liver disease rarely leads to hepatic fibrosis and liver failure. Hepatomegaly and abdominal pain may be present. Cysts are usually first noticed during puberty.