Immunohistochemistry on cell blocks for diagnosis of malignancy in abdomino-pelvic lesions and ascitic fluid cytology at a rural cancer center: A paradigm shift in cancer management

Background: Cell block preparation is routine practice in cytopathology these days because of its pivotal role in increasing diagnostic yield and ancillary studies. In the present era of personalized medicine in oncology, ancillary techniques such as immunohistochemistry (IHC) and molecular analysis are gaining more importance. Methods: A retrospective study was conducted in the Department of Pathology, over 6 months, which included 144 cases of Fine Needle Aspiration Cytology (FNAC) of abdominopelvic masses and 105 cases of ascitic fluids. Cell blocks and conventional smears were prepared simultaneously in all cases. IHC was applied on cell blocks and analyzed. Results: IHC was performed on cell blocks in 76 cases of FNA and 53 cases of ascitic fluids. Based on IHC, liver lesions (50 cases) were categorized into metastatic carcinomas with a suggested primary site (45.0%), hepatocellular carcinoma (12.2%), neuroendocrine tumors (16.3%), and malignant melanoma (2%). Using MOC-31 and WT-1, ascitic fluid samples were categorized into benign and malignant. Forty-one out of 53 cases of fluids were diagnosed as metastatic adenocarcinomas with the ovary as the most common primary site. Conclusion: A panel of IHC markers, though not specific alone when applied to cell blocks in a careful clinical and morphological context leads to a rapid and accurate diagnosis. This in turn obviates the need for biopsy in severely ill patients. An astute pathologist can provide accurate results with judicious use of IHC on cell blocks and may bring a sigh of relief for many cancer patients by averting the need for biopsy.