Isolated hemihyperplasia in an infant: an overlooked sign for wilms tumor development.

Background: Children with overgrowth syndromes including isolated hemihyperplasia have an increased risk for developing embryonal tumors, particularly Wilms' tumor and hepatoblastoma. Screening with sonography has been suggested as a method of identifying these tumors while they are still at an early stage.

Case Presentation: We describe an infant diagnosed with Wilms tumor in whom isolated hemihyperplasia had been overlooked by several physicians prior to the tumor diagnosis.

Conclusion: We recommend tumor surveillance for all patients with Beckwith-Wiedemann syndrome and isolated hemihyperplasia at least for the first six years of life since full molecular characterization of every patient is not readily available.