Cystic nephroma: an emerging entity.

Cystic nephroma is a rare lesion, but there has been an increased number of cases reported in the recent literature. Most cases have been discovered incidentally either on routine examination or during radiological investigations. There are two peaks of incidence, one in childhood and one in middle age and the condition is often wrongly presumed to be a malignant tumor. Cystic nephroma is a benign neoplasm and it can be confidently diagnosed using modern imaging techniques and tissue analysis. Classically, the treatment of cystic nephroma has been simple nephrectomy, although a few cases have been treated by enucleation. Simple nephrectomy is the treatment of choice in children as the diagnosis in the young is less exact and a cure is assured. In some adult patients it is reasonable to pursue a conservative policy with regular clinical and ultrasound examinations.