Insights from a patient with chronic lymphocytic leukemia complicating ALK⁺ anaplastic large cell lymphoma

Chronic lymphocytic leukemia (CLL) that transforms into a more aggressive lymphoma has been termed Richter syndrome (RS). CLL with T-cell neoplasia is rarely reported; those with ALK⁺ anaplastic large cell lymphoma (ALCL) are also exceedingly rarely reported. A 63-year-old woman from the south of China presented with generalized lymphadenectasis and fever; she already had a prior diagnosis of CLL 9 years ago. As per her current diagnosis, it was CLL with ALK⁺ ALCL. The two-lymph node and bone marrow biopsies presented two types of cellular groups: i) left cervical lymph node biopsy suggested CLL (Ki67: 10%), along with bone marrow biopsy exhibited enhancement of the small lymphocytes (30%) with scant cytoplasm, round or irregular cell nuclei, and massive amounts of chromatin. Large cells (< 1%) that expressed CD30 and ALK were visible; The results of immunohistochemistry were as follows: CD20 (weak positive); PAX5 (positive); CD23 and CD5 (weak positive); and CD3, CD10, and CyclinD1 (negative); ii) left supraclavicular lymph node biopsy suggested ALK⁺ ALCL (Ki67: 70%). The final diagnosis was CLL with ALCL. The mechanisms of this condition are not fully understood, which might be associated with chronic stimulation of T cells by CLL cells along with immune dysfunction.