Abstract

Background: The impact of diagnostic immunohistochemistry for the surgical pathology is legendary especially when it provides true identity of undifferentiated tumours. This not only is important for prognostication & therapy but also provide further insights into the pathobiology of these tumours. Aims &
Objective: This study was undertaken to determine the role and significance of immunohistochemistry for accurate diagnosis and subtyping of undifferentiated malignant tumours as it is essential in guiding therapy and prognosis. Material and Methods: Immunohistochemical staining (IHC) performed was based on Peroxidase Antiperoxidase (PAP) method on paraffin sections, using appropriate mono/polyclonal antibodies. Total 74 cases including six consultation cases were studied from August 2008 to November 2011, which were reported as undifferentiated or poorly differentiated malignant tumor using routine hematoxylin- eosin stains.
Results: The histopathology and IHC reports of 74 tumours were reviewed and assigned to appropriate categories. It was possible to arrive at a diagnosis in 73 cases (98.65%) with the help of IHC. Carcinoma was the commonest diagnosis (27 cases, 36.50%) followed by lymphoma (18 cases, 24.32%), sarcoma (14 cases, 18.92%), malignant melanoma (3 cases, 4.05%) and neuroblastoma (3 cases, 4.05%). Conclusion: Immunohistochemistry is helpful in the majority of difficulties arising during histological diagnosis of undifferentiated malignant tumours and serves as a diagnostic, prognostic, and predictive tool.