Perirenal Ultrasound Abnormality: When to Think about Xanthogranulomatous Erdheim-Chester Disease - Stefanini, Bernardo; Serio, Ilaria; Fernández Ramos, Julián; Ribichini, Danilo; Modestino, Francesco; Piscaglia, Fabio (Ultraschall in der Medizin - European Journal of Ultrasound, 2023)