Immunocytochemical staining of serous effusions: an additional method in the routine cytology practice?

Area of Science:

• Cytopathology
• Immunocytochemistry
• Oncology

Background:

• Serous fluid analysis is crucial for diagnosing various conditions, including malignancy.
• Traditional cytomorphology can sometimes be insufficient for definitive diagnosis in serous effusions.
• Immunocytochemistry offers potential for improved diagnostic accuracy.

Purpose of the Study:

• To evaluate the utility of a panel of antibodies, specifically Ber-EP4 and EMA, in differentiating benign from malignant cells in serous fluids.
• To assess the impact of immunocytochemistry on the detection rate of malignant cases in serous effusions.
• To establish reliable immunocytochemical staining profiles for accurate diagnosis.

Main Methods:

• A prospective study involving 100 serous fluid samples.
• Cytomorphologic analysis combined with immunocytochemistry using a panel of antibodies, including Ber-EP4 and Epithelial Membrane Antigen (EMA).
• Classification of staining patterns into benign and malignant profiles.

Main Results:

• Three distinct immunocytochemical staining profiles were identified: benign (negative for Ber-EP4/CEA), malignant epithelial (Ber-EP4 and EMA positive), and malignant mesothelial (EMA positive).
• Application of these profiles increased the recognition of malignant cases from 19 to 38.
• Two cases showed a false-positive malignant epithelial profile, highlighting the need for correlation with other data.

Conclusions:

• Immunocytochemistry with anti-Ber-EP4 and anti-EMA is a valuable addition to routine cytomorphologic analysis of serous fluids.
• This approach significantly enhances the detection of malignancy in serous effusions.
• Results must be correlated with cytomorphology, histology, and clinical information for accurate interpretation and to mitigate false positives.