Development of lymphomas is estimated to occur in 5–15% of patients with CLL, to a histological appearance resembling either diffuse large B-cell lymphoma (DLBCL) (in 80% of cases) or Hodgkin lymphoma (HL) in the remaining cases. Lymphomatous transformation is characterised by bulky lymphadenopathy, rapid nodal enlargement, extra nodal disease, B-symptoms and increased levels of lactate dehydrogenase (LDH). CLL patients with lymphomatous transformation have significantly poorer outcomes than patients with histologically similar de novo lymphomas (Oscier et al., 2012).
Depending on the histological subtype of lymphomatous transformation, UK guidelines recommend that patients who are suitable for intensive therapy should receive regimens currently employed for either primary DLBCL or HL (preferably in the context of a clinical trial). Younger patients with the DLBCL type of transformation who achieve a good response are potentially suitable for alloSCT (Oscier et al., 2012).