Richter's syndrome presenting as primary central nervous system lymphoma. Transformation of an identical clone

Area of Science:

• Hematology
• Neurology
• Oncology

Background:

• Chronic lymphocytic leukemia (CLL) is a common B-cell malignancy.
• Central nervous system (CNS) involvement in CLL is rare and often associated with transformation.
• Richter's syndrome describes the transformation of CLL into a more aggressive lymphoma.

Observation:

• A patient presented with simultaneous chronic lymphocytic leukemia (CLL) and a central nervous system (CNS) large cell lymphoma.
• Phenotypic differences were observed between the peripheral blood CLL and the CNS lymphoma.
• The CNS tumor showed an aneuploid cell population, indicating genetic instability.

Findings:

• Identical immunoglobulin gene rearrangements in both CLL and CNS lymphoma provided evidence of a shared clonal origin.
• Morphological distinctness and genetic alterations suggest clonal evolution from a common precursor.
• This case represents isolated parenchymal CNS involvement by large cell transformation of CLL, a previously undescribed entity.

Implications:

• Highlights the potential for CLL to undergo transformation into aggressive CNS lymphoma.
• Underscores the importance of genetic analysis in distinguishing primary CNS lymphoma from secondary involvement in CLL patients.
• Contributes to understanding the spectrum of CNS involvement and Richter's syndrome in chronic lymphocytic leukemia.