RESUMEN
OBJECTIVE: The results of in situ dissolution of a cystine calculus is described. This approach was attempted in a female patient for whom surgery was not considered to be the best therapeutic option. METHODS: An obstructive cystine calculus was treated by in situ litholysis using N-acetylcysteine applied locally via two percutaneous nephrostomies and adjuvant oral metaphylaxis. The patient had a long clinical history of lithiasis that had also required surgery and a family history of cystinuria. RESULTS: In situ litholysis completely dissolved the cystine calculus and avoided the need for a complex surgery. The procedure and a pharmacological analysis are presented. CONCLUSIONS: In our view, this procedure is practical, carries minimal morbidity and should be considered in the management of cystine calculus.