A Rare Case of Renal Failure Caused by T‐Cell Prolymphocytic Leukaemia Infiltration

T-cell prolymphocytic leukaemia (T-PLL) is an aggressive and rare post-thymic T cell malignancy, highly refractory to conventional cytotoxic chemotherapeutics. While extranodal involvement is common, solid organ invasion is rare. We present the case of a 76-year-old man who developed acute renal failure secondary to T-PLL renal infiltration. On day four of his admission, prior to commencing alemtuzumab, his creatinine rose from 133 μmol/L to 390 μmol/L, with anuria. Renal biopsy demonstrated an infiltrate of monomorphic, mononuclear cells positive for a STAT5B mutation, consistent with T-PLL infiltration. He required haemodialysis, but was treated with pulsed methylprednisolone and alemtuzumab, with excellent renal recovery, although remission was not achieved. This case demonstrates that renal leukaemic infiltration must be considered in T-PLL patients with rapidly progressive renal failure, and that solid organ invasion should not contraindicate timely commencement of T-PLL-directed therapy with alemtuzumab.