Peracute onset of severe tumor lysis syndrome immediately after 4 Gy fractionated TBI as part of reduced intensity preparative regimen in a patient with T-ALL with high tumor burden.

We report a 30-year-old patient with therapy-refractory T-ALL undergoing unrelated allogeneic PBSCT. He developed severe tumor lysis syndrome (TLS) with extreme biochemical changes, cardiac and neurological symptoms and dialysis-dependent acute renal failure after TBI (4 Gy) on the first day of reduced intensity conditioning (RIC) for unrelated allogeneic PBSCT. The patient's clinical condition was stabilized after beginning daily hemodialysis and treatment for disturbed electrolytes, metabolic acidosis and plasma coagulation, as well as reduction of uric acid by rasburicase. The conditioning therapy and the allogenic PBSCT were scheduled according to the preparative regimen. According to our knowledge, severe TLS induced by 4 Gy TBI has not been reported so far. Regimen-related toxicity using RIC regimen was mild, allowing 30-50% of the patients to have an entirely outpatient transplantation. However, we would like to point out that severe TLS could also complicate PBSCT using RIC regimens in patients with relatively radiation-sensitive malignancies and high tumor burden.