Mesoblastic nephroma presenting as a haemorrhagic cyst.

Two cases of haemorrhagic renal cyst presenting in the neonatal period are described. Ultrasound examination, excretory urogram, and MRI, gave diagnosis in the second case. The remarkable histopathologic pattern of these two cases has led to propose correct diagnosis of pure cystic mesoblastic nephroma, an unusual variety of mesoblastic nephroma.