CD56+/CD4+ lymphomas and leukemias are morphologically, immunophenotypically, cytogenetically, and clinically...

Area of Science:

• Hematology
• Immunology
• Oncology

Background:

• CD56 is a neural adhesion molecule expressed on Natural Killer (NK) cells and a subset of CD8+ T cells.
• The CD56+/CD4+ lymphocyte phenotype is typically rare in normal physiology.
• Elevated CD56+/CD4+ lymphocytes can be associated with immunosuppression, chronic inflammation, and autoimmune diseases.

Observation:

• This study reports four cases of lymphomas/leukemias exhibiting the uncommon CD56+/CD4+ phenotype.
• Two cases were identified as T-cell lymphomas, and two as true NK-cell lymphomas.
• T-cell lymphomas presented with large granular lymphocyte morphology and splenomegaly, with variable clinical courses.
• NK-cell lymphomas displayed blastic morphology, initial skin involvement, and aggressive clinical progression, including acute leukemia and post-transplant recurrence.

Findings:

• Cytogenetic analysis did not reveal consistent chromosomal abnormalities across the studied cases.
• One NK-cell lymphoma with acute leukemia showed a t(2;5) translocation but was negative for CD30 and anaplastic lymphoma kinase (ALK).
• The heterogeneity of CD56+/CD4+ lymphomas/leukemias is highlighted, with a potential distinct subgroup of NK lymphoblastoid lymphomas of the skin.

Implications:

• The findings suggest that CD56+/CD4+ lymphomas/leukemias represent a diverse group of hematologic malignancies.
• Recognition of a potential distinct subtype of aggressive NK lymphoblastoid lymphoma, particularly with cutaneous manifestations, is crucial for diagnosis and treatment.
• Further research is warranted to elucidate the specific biology and clinical behavior of these rare lymphoid neoplasms.