Imaging findings in recurrent extramedullary leukaemias

Acute leukaemias are relatively common malignancies. Treatment has advanced significantly in the recent past and there has been improved patient survival. This improved initial response is leading to an increasing number of cases of relapse. Extramedullary relapse occurs in a wide variety of locations with varying presentations, imaging findings and differentials. The pathophysiology and clinical course of recurrent extramedullary myeloid and lymphocytic leukaemias are reviewed in this article. The wide variety of imaging findings associated with many important sites of recurrence and the associated differential diagnosis are discussed and illustrated.