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.
Signs and Symptoms. Kidney cysts usually do not cause any symptoms. Simple kidney cysts may cause complications like: 1  Abdominal or lumbar pain: due to the displacement of abdominal organs, rupture or bleeding of the renal cyst. 2  Hematuria: due to rupture of a renal cyst into the pyelocaliceal system.igns and Symptoms. Kidney cysts usually do not cause any symptoms. Simple kidney cysts may cause complications like: 1  Abdominal or lumbar pain: due to the displacement of abdominal organs, rupture or bleeding of the renal cyst. 2  Hematuria: due to rupture of a renal cyst into the pyelocaliceal system.