Role of Immunohistochemistry in Categorisation of Metastatic Tumours of Liver: A Cross-sectional Observational Study

Introduction: The liver is the body’s largest solid organ and receives a dual blood supply, making it an easy target for metastases from both extra-abdominal and abdominal lesions. In adults, the most common sites of primary lesions are the breast, colon, lung and pancreas. Liver biopsies are pivotal for managing patients with metastatic diseases, aiding in diagnosis and treatment planning. When primary cancer sites are undetectable, the diagnosis often falls under Carcinoma of Unknown Primary (CUP), which carries a poor prognosis. Immunohistochemistry (IHC) is critical in such cases, using antibodies to identify the cancer’s origin when other methods fail. This technique is vital for confirming known malignancies and diagnosing elusive ones, thus informing treatment and improving patient outcomes. Aim: To study the role of IHC in the categorisation of metastatic tumours of the liver. Material and Methods: A cross-sectional observational study was conducted in the Department of Pathology, Sri Aurobindo Medical College and Postgraduate (PG) Institute, Indore, Madhya Pradesh, India, between March 2021 and April 2024. Core needle biopsy samples of 65 cases were processed and analysed for Haematoxylin and Eosin (H&E) stain and IHC markers. Data on demographics and lesion characteristics were entered into Microsoft Excel and analysed with a trial version of Statistical Package for the Social Sciences (SPSS). Significance was assessed using Pearson’s Chi-square test, with a p-value