Cystic lesions in the liver and kidneys are common incidental findings. They are generally benign and require no treatment. They can appear sporadically or as part of a syndrome, and are characterised by their anechoic structure and posterior enhancement in ultrasound imaging. Increased size, haemorrhage or infection of a cyst can lead to development of symptoms. Along with surgical options and laparoscopic cyst fenestration, ultrasound-guided sclerotherapy of symptomatic cysts represents an effective and safe minimally invasive treatment option.