HLH and TET2 Mutation Presenting after First Cycle of CLL Treatment

Area of Science:

• Hematology
• Oncology
• Immunology

Background:

• Chronic lymphocytic leukemia (CLL) is a common B-cell malignancy.
• Bendamustine and rituximab are standard therapies for CLL.
• Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome.

Purpose of the Study:

• To report a rare case of HLH and TET2-mutated myeloid neoplasm development after CLL treatment.
• To highlight the diagnostic challenges and management of this complex clinical scenario.

Main Methods:

• Case report detailing patient presentation, treatment, and outcomes.
• Review of bone marrow biopsy findings, including cytogenetics and molecular analysis.
• Clinical assessment for HLH criteria and response to therapy.

Main Results:

• Development of HLH and a TET2-mutated myeloid neoplasm following bendamustine and rituximab therapy for CLL.
• Patient presented with pancytopenia and laboratory findings consistent with HLH.
• Bone marrow biopsy revealed persistent CLL, fibrosis, megakaryocytic proliferation, and TET2 mutation.
• Recovery achieved with dexamethasone and G-CSF support.

Conclusions:

• Bendamustine and rituximab can precipitate HLH and unmask underlying myeloid neoplasms in CLL patients.
• Early recognition and multidisciplinary management are crucial for favorable outcomes.
• TET2 mutations may play a role in the pathogenesis of therapy-induced HLH.