The "salt and pepper" pattern on renal ultrasound in a group of children with molecular-proven diagnosis of ciliopathy-related renal diseases.

BACKGROUND: While typical ultrasound patterns of ciliopathy-related cystic kidney diseases have been described in children, ultrasound findings can overlap between different diseases and atypical patterns exist. In this study, we assessed the presence of the "salt and pepper" pattern in different renal ciliopathies and looked for additional ultrasound features.
METHODS: This single-center, retrospective study included all patients with a molecular-proven diagnosis of renal ciliopathy, referred to our center between 2007 and 2017. Images from the first and follow-up ultrasound exams were reviewed. Basic ultrasound features were grouped into patterns and compared to genetic diagnoses. The "salt and pepper" aspect was described as enlarged kidneys with heterogeneous, increased parenchymal echogenicity.
RESULTS: A total of 41 children with 5 different renal ciliopathies were included (61% male; median age, 6 years [range, 3 days to 17 years]). The "salt and pepper" pattern was present in 14/15 patients with an autosomal recessive polycystic kidney disease (ARPKD). A similar pattern was found in 1/4 patients with an autosomal dominant polycystic kidney disease and in 1/11 patients with HNF1B mutation. Additional signs found were areas of cortical sparing, comet-tail artifacts, and color comet-tail artifacts.
CONCLUSION: Although the "salt and pepper" ultrasound pattern is predominantly found in ARPKD, it may be detected in other ciliopathies. The color comet-tail artifact is an interesting sign when suspecting a renal ciliopathy in case of enlarged hyperechoic kidneys with no detectable microcysts on B-mode grayscale ultrasound.