ALK-positive anaplastic large cell lymphoma in a patient with chronic lymphocytic leukemia.

This article reports the case of a 59-year-old patient with an 8-year history of chronic lymphocytic leukemia (CLL), prostate carcinoma, and squamous cell carcinoma who developed an ALK-positive anaplastic large cell lymphoma (ALCL). Lymph node and bone marrow biopsies showed 2 distinct morphologic populations: (a) the CLL component showing a diffuse monomorphous infiltrate of small lymphocytes with the typical immunophenotype showing positive CD20, CD5, CD23, and κ light chain restriction and (b) the ALCL component showing large anaplastic pleomorphic cells positive for CD30, CD45, ALK, CD45Ro, CD4, and vimentin. Polymerase chain reaction performed on the lymph node for immunoglobulin heavy chain and T-cell receptor γ and β showed gene rearrangements after macrodissection of morphologically distinct populations, indicating confirmed genetically distinct populations. Despite intensive chemotherapy, the patient died. This case represents the rare occurrence of an ALK-positive ALCL developing in a patient with CLL.