You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is A renal tumour which has a multicentric origin - and explain in detail?
Wilms tumor 

Wilms tumor is the most common primary renal tumor of childhood.
The usual age for diagnosis is 2-5 years.
Approximately 5% to 10% of Wilms tumors involve both kidney, either simultaneously or one after the other.
Nephrogenic rests are the precursor lesions of Wilms Tumor.
Most children with Wilms tumors present with a large abdominal mass.
Less common presentations are hematuria, abdominal pain, intestinal obstruction, and hypertension.
"10% of Wilms tumors are either bilateral or multicentric at the time of diagnosis". - Robbin's