Leukaemic Effusion or Extramedullary Haematopoiesis?

Area of Science:

• Hematology
• Oncology
• Cytopathology

Background:

• Acute myeloid leukaemia (AML) can present with extramedullary disease.
• Pleural effusions are a known, though less common, manifestation of AML.
• Marrow fibrosis can complicate the clinical picture and diagnostic interpretation in AML.

Purpose of the Study:

• To describe a rare case of leukaemic pleural effusion in AML with significant marrow fibrosis.
• To highlight the potential for misinterpretation of cytologic findings in pleural fluid.
• To emphasize the importance of integrated diagnostic approaches in complex AML cases.

Main Methods:

• Case report detailing clinical presentation, laboratory findings, and diagnostic procedures.
• Cytologic evaluation of pleural fluid for atypical cells.
• Integration of morphology, immunophenotyping, clinical history, and radiologic findings.

Main Results:

• Cytologic analysis of pleural fluid revealed numerous large atypical cells.
• Morphology of these cells was consistent with dysplastic megakaryocytes.
• The findings were ultimately attributed to leukaemic infiltration.

Conclusions:

• Leukaemic pleural effusion in AML with marrow fibrosis can be morphologically mistaken for other conditions.
• Accurate diagnosis requires careful attention to cytomorphologic features and integration of multiple data sources.
• Recognizing this diagnostic pitfall is crucial for appropriate patient management and treatment.