Immunocytochemistry of effusions: Processing and commonly used immunomarkers

Abstract

Definitive cytopathological interpretation of some of the effusion fluids may not be possible based on cytomorphological evaluation alone. As discussed in other reviews, this is due to various reasons specifically applicable to effusion fluids including remarkably wide morphologic spectrum of reactive mesothelial cells overlapping with some well to moderately differentiated metastatic carcinoma. The challenge is subject to various factors including level of interpreter training or experience, institutional demographics (such as type of prevalent diseases, predominant sex and age group), technical advances in ancillary support, and expertise in cytopreparatory processing. In such cases immunohistochemistry performed on cell-block sections is simple objective adjunct with or without other ancillary techniques. Ongoing increase in number of immunomarkers along with rabbit monoclonal antibodies with relatively higher affinity is further refining this field. SCIP (subtractive coordinate immunoreactivity pattern) approach, discussed as separate dedicated review article, facilitates refined interpretation of immunoreactivity pattern in coordinate manner on various serial sections of cell-blocks. However, many variables such as delay after specimen collection, specimen processing related factors including fixation and storage; ambient conditions under which paraffin blocks are archived (for retrospective testing); antigen retrieval method; duration of antigen retrieval step; antibody clone and dilution; and antibody application time are common with application of immunohistochemistry in other areas. This review is dedicated to highlight technical aspects including processing of effusion specimens for optimum immunocytochemical evaluation along with commonly used immunomarkers in effusion cytopathology. This review focuses on the technical and general information about various immunomarkers.

A comparative study of cytological processing techniques in hemorrhagic effusion

“…Because of numerous technical and quality control issues, it is ideal to have cell-block for immunocytochemistry. [ 19 - 21 ] Smears treated with fixative containing GAA has shown high false positive results on hybrid capture 2 human papillomavirus testing. [ 17 ] Ammonium chloride-based erythrocyte lysing reagent, similar to that used for flow cytometry is relatively simpler and inexpensive without compromising the immunoprofile integrity in preparing cell-block of hemorrhagic effusions.…”

“…[ 17 ] Ammonium chloride-based erythrocyte lysing reagent, similar to that used for flow cytometry is relatively simpler and inexpensive without compromising the immunoprofile integrity in preparing cell-block of hemorrhagic effusions. [ 19 - 21 ]…”

Urine Cytology and Axillary Testing for Interpretation and Follow-Up of Urinary Tumors

“…The Paris System working group was composed of pathologists and urologists, and met in 2013 at the venue of the International Congress of Cytology, proposing the Paris system to standardize urine cytology 47 . In interpretation of urine samples that often contain few and misrepresented cells, immunocytology is an accepted method 48,49 .…”