text: The patient underwent acute oliguric renal failure, which required treatment with hyperhydration, urine alkalinization, urate oxidase and hemodialysis, with a fatal evolution.In conclusion, the present case report has several peculiarities: that of being one of the rare examples of spontaneous TLS, that of showing an exceptionally severe hyperuricemia, probably the highest ever reported in the literature, and that of the possible increased risk of tumours in patients with Crohn s disease taking inmunosuppressives and/or TNF antagonists.