A 45-year-old Caucasian male with a 16-year history of HIV-1 infection and a 5-year history of ileocecal nonHodgkin lymphoma was admitted to the emergency room with fever, and abdominal pain and distension. In the previous month, he noticed abdominal pain. A CT scan and colonoscopy were performed and confirmed tumour relapse involving the distal ileum, caecum and right colon. At admission, the patient was dehydrated, hypotensive, tachycardic, tachypneic and febrile. He presented ascites and a petrous mass in the right lower abdominal quadrants. Oliguria was documented. Laboratory tests (Table 1) revealed anaemia, elevation of acute-phase reagents, renal dysfunction, hypernatraemia, metabolic acidosis and hypoxaemia. Elevation of creatine kinase and lactic dehydrogenase, and hyperphosphataemia, hypocalcaemia, hyperuricaemia and hyperkalaemia were also diagnosed. Abdominal plain did not reveal air–fluid levels, and abdominal CT scan showed ascites and a voluminous mass in the ileon, caecum and right colon. A paracentesis was performed and an exsudate with high cellularity (28.160/mm3) with numerous blasts was drained. Fluid resuscitation was started and vasoactive support was needed. The patient required ventilatory support and was admitted to the Department of Intensive Medicine. Empirical antibiotherapy (meropenem) and rasburicase (0.2 mg/kg, single dose) were administered. There was refractory oliguria, and continuous venovenous haemodiafiltration was started. The abdomen remained distended, haemoglobin decreased by 2 g/dL and 2 units of erythrocyte concentrate were administered. Cultures were negative. Despite the central venous pressure of