Diffuse renal cystic disease in children: morphologic and genetic correlations

During a 5-year period, we evaluated seven infants and two fetuses who presented with enlarged, hyperechoic kidneys. In each, the initial clinical diagnosis was autosomal recessive polycystic kidney disease (ARPKD). Among the seven unrelated infants were three Caucasian and four African-American infants. No syndromic stigmata were evident in any of these infants. At the time of the initial evaluation, the family data were incomplete for four infants. The two fetuses were presumed to be at-risk for ARPKD based on the diagnosis in previous siblings. Renal histopathology was evaluated in all nine cases and revealed a spectrum of cystic disease ranging from ARPKD to glomerulocystic kidney disease to autosomal dominant polycystic kidney disease to diffuse cystic dysplasia. In the eight cases for whom liver histopathology was available, varying degrees of biliary dysgenesis were evident. We present a detailed analysis of the key histopathological features in each case and discuss the histopathological findings in an embryological context. In addition, we address the current role of molecular genetics in the diagnostic evaluation.