APIMC243889241 - CME/CMLE - Body Fluid Microscopy #1: Small Lymphocytic Lymphoma, Chronic Lymphocytic Leukemia-APIMC243889241- Educational Activity

APIMC243889241- Educational Activity

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This educational commentary by Dr. Padmini A. Manrai discusses the characteristics and diagnosis of pleural effusions associated with Small Lymphocytic Lymphoma (SLL) and Chronic Lymphocytic Leukemia (CLL). Pleural effusions, fluid accumulations in the pleural cavity, can result from various causes including malignancy, infection, heart failure, and inflammation. SLL and CLL represent the same B-cell non-Hodgkin lymphoma disease spectrum, with SLL primarily involving lymph nodes and CLL involving blood and bone marrow. CLL is the most common adult leukemia in Western countries.<br /><br />Patients with SLL/CLL can develop pleural effusions, often due to infections like pneumonia; however, direct involvement of the pleural cavity by malignant lymphoma/leukemia cells, termed chylothorax, can occur in advanced stages. Cytologic evaluation of pleural fluid is critical for diagnosis and involves differentiating malignant lymphoma cells from reactive mesothelial and common inflammatory cells such as neutrophils and eosinophils. Malignant small B-cell lymphoma cells are slightly larger than typical lymphocytes, have a high nuclear-to-cytoplasmic ratio, and display clumped “soccer ball” chromatin. In contrast, reactive mesothelial cells have abundant dense cytoplasm with a characteristic ruffled “lacy skirt” and form cell clusters that maintain distinct borders (“windows”), unlike malignant cells that tend to overlap.<br /><br />Inflammatory cells such as segmented neutrophils (with multilobed nuclei) and eosinophils (containing reddish-orange granules) are commonly seen in malignant effusions. Immunohistochemical and flow cytometric analyses are important confirmatory tools, but detailed morphological examination helps prioritize samples for advanced testing.<br /><br />Laboratory assessment of pleural effusions includes gross examination, measurement of analytes like protein and lactate dehydrogenase, specific gravity determination, and microscopic evaluation, aiding in classifying effusions as transudates or exudates, with malignancy typically causing exudates.<br /><br />In summary, careful microscopic evaluation is essential in identifying SLL/CLL involvement in pleural effusions, distinguishing malignant cells from reactive and inflammatory populations, thus guiding prompt and appropriate clinical management.

Keywords

Small Lymphocytic Lymphoma

Chronic Lymphocytic Leukemia

Pleural Effusion

Malignant Lymphoma Cells

Reactive Mesothelial Cells

Cytologic Evaluation

Chylothorax

Immunohistochemistry

Flow Cytometry

Exudative Effusions