Value of Ki67 immunostain in identification of malignancy in serous effusions

Diagnostic Utility of Epithelial Membrane Antigen (EMA) and Calretinin (CAL) in Effusion Cytology

INTRODUCTION

Fluid cytology and subsequent utilization of immunocytology on cell block is being used commonly for increasing the diagnostic accuracy in effusion cytology.

AIM

To do cytological analysis of fluids and evaluate the role of Epithelial Membrane Antigen (EMA) and Calretinin (CAL) to differentiate between reactive and malignant cell in pleural and peritoneal fluids.

MATERIALS AND METHODS

This was a prospective study carried out in Department of Pathology, Shri Guru Ram Rai Institue of Medical and Health Science, for a period of 18 months from January 2014 to June 2015. A total of 253 samples of pleural and peritoneal fluid were studied by May-Gruenwald-Giemsa (MGG) stain and Papanicolaou (Pap) staining. In 73 cases which were suspicious for malignancy, cell blocks were prepared and IHC was done using two immunomarkers- EMA and CAL.

RESULTS

A total of 253 cases of effusion cytology were studied out of which 73 were found positive for malignant cells. Maximum cases of malignant cells or atypical cells were seen in peritoneal fluid. A total of 34 cases were histologically positive for malignancy. All these cases showed strong membranous and cytoplasmic positivity for EMA. Most of cases also showed 2%-5% positivity for CAL. There were 38 cases categorized as atypical or reactive mesothelial cell hyperplasia. These cases showed nuclear and cytoplasmic staining for calretinin and none of these were positive for EMA, although 5 cases showed score 2-3, which was considered as negative.

CONCLUSION

The distinction between reactive and malignant mesothelial cells in cytological specimens can be problematic. A combination of CAL and EMA may help in accurate diagnosis.

Significance of cell proliferation markers (Minichromosome maintenance protein 7, topoisomerase IIalpha and Ki-67) in cavital fluid cytology: can we differentiate reactive mesothelial cells from malignant cells?

The aim of this study was to evaluate whether immunocytochemical expressions of proliferation markers, such as minichromosome maintenance protein 7 (MCM 7), topoisomerase IIalpha (topo IIalpha), and Ki-67, in reactive mesothelial cells and malignant cells obtained from cavital fluids could be useful for their differential diagnosis. Samples diagnosed as reactive mesothelial cells (14 cases) or malignant tumors (28 cases) in cavital fluids were examined. Immunocytochemical staining of MCM 7, topo IIalpha, and Ki-67 was performed with the universal immunoperoxidase polymer method. In reactive mesothelial cells, MCM 7 was stained in a fine granular pattern and its distribution was uniform in the nuclei. Topo IIalpha and Ki-67 were stained in a coarse granular pattern and the distributions were the same as MCM 7. In contrast, in malignant cells, MCM 7 was stained in an irregular and fine granular pattern, and topo IIalpha and Ki-67 were stained in a uniform and coarse granular pattern. Labeling indices of MCM 7 (cut-off value; 30%, sensitivity; 100%, and specificity; 100%), topo IIalpha (cut-off value; 15%, sensitivity; 89.3%, and specificity; 92.9%) and Ki-67 (cut-off value; 30%, sensitivity; 64.3%, and specificity; 92.9%) of malignant cells were significantly higher than those of reactive mesothelial cells. MCM 7, topo IIalpha, and Ki-67 are different types of cell proliferation markers. MCM 7 and topo IIalpha, in particular, could be reliable tools for differential diagnosis between reactive mesothelial cells and malignant cells.

Serous effusions: diagnosis of malignancy beyond cytomorphology. An analytic review

In this brief review, the role of various ancillary techniques to detect malignancy in effusion fluid are evaluated and discussed. The data were collected from a large number of research articles published in various medical journals. The role of these techniques to increase the diagnostic accuracy in serous effusions is emphasised.