A case of CD138-/CD19+/CD4+ IgD plasma cell leukemia

Area of Science:

• Hematology
• Oncology
• Clinical Cytometry

Background:

• Plasma cell leukemia (PCL) is a rare and aggressive hematologic malignancy.
• PCL involves clonal proliferation of atypical plasma cells, sharing similarities with multiple myeloma (MM).
• This case presents IgD PCL with a highly unusual immunophenotype.

Purpose of the Study:

• To report a unique case of IgD PCL.
• To highlight the diagnostic utility of immunophenotyping in challenging PCL cases.
• To describe an atypical CD138-/CD19+/CD4+ phenotype in PCL.

Main Methods:

• Analysis of peripheral blood and bone marrow samples.
• Conventional morphology, flow cytometry, and immunohistochemistry were employed.
• Patient was a 37-year-old with aggressive plasma cell dyscrasia.

Main Results:

• Peripheral blood analysis met PCL diagnostic criteria (>20% plasma cells, >2x10^9/L).
• Flow cytometry and immunohistochemistry revealed a CD138-/CD38+/CD19+/CD4+/CD56-/CD117- phenotype.
• The identified phenotype was highly atypical for PCL.

Conclusions:

• PCL diagnosis is primarily based on peripheral blood smear findings.
• Immunophenotyping is valuable for diagnosing difficult PCL cases.
• Atypical immunophenotypic findings should not impede PCL diagnosis when clinical and morphological evidence is clear.