Immunocytochemistry of effusions: Processing and commonly used immunomarkers

Area of Science:

• Cytopathology
• Immunohistochemistry
• Molecular Pathology

Background:

• Cytopathological interpretation of effusion fluids can be challenging due to overlapping morphology between reactive mesothelial cells and metastatic carcinoma.
• Factors like interpreter experience, institutional demographics, and technical advancements influence diagnostic accuracy.

Purpose of the Study:

• To highlight technical aspects of processing effusion specimens for optimal immunocytochemical evaluation.
• To review commonly used immunomarkers in effusion cytopathology.

Main Methods:

• Immunohistochemistry on cell-block sections serves as an objective adjunct diagnostic tool.
• The subtractive coordinate immunoreactivity pattern (SCIP) approach refines interpretation of immunoreactivity patterns.

Main Results:

• Immunohistochemistry, particularly with advancements in immunomarkers and antibodies, refines diagnostic capabilities in effusion cytology.
• Standardization of technical variables is crucial for reliable immunohistochemistry results.

Conclusions:

• Immunocytochemistry is essential for definitive interpretation of effusion fluids when cytomorphology alone is insufficient.
• Optimizing specimen processing and understanding technical variables are key for accurate immunocytochemical evaluation in effusion pathology.