Original Article This work is licensed under the Creative Commons Attribution 4.0 License. Published by Pacifc Group of e-Journals (PaGe) Immunohistochemistry: Not as Sensitive as Expected for Detecting Bone Marrow Micrometastases in Cases of Epithelial Malignancies? Introduction The most common malignancies are derived from simple epithelia of breast, lung, colon, prostate, ovaries, and endometrium. Carcinomas from these sites usually metastasize to regional lymph nodes and other organs, such as lung, brain, liver and bones. Among various epithelial malignancies breast (28.8%) and lung (23.3%) are common to metastasize to bone marrow [1,2] . The diagnosis of the metastatic carcinoma can be very difcult. The determination of the primary site of the metastasis is a challenge to both oncologists and pathologists, having potential important clinical and therapeutic consequences [3] . Bone metastasis is a catastrophic complication for intractable pain and other clinical problems such as fracture after trivial injury, spinal cord compression, and hypercalcemia; it also signifes that the malignant process is incurable [4] . More than 30 years ago Sloane et al (1980) [4] introduced the term ‘micro metastasis’ to describe isolated disseminated tumor cells which are not detected by conventional staging methods. Micro metastasis are microscopic deposits (less than 2mm) of malignant cells that are segregated spatially from the primary tumor and depend on neo vascular formation (angiogenesis) to propagate. It was concluded by some researchers that the concept of micro metastasis had resulted in paradigm shift in the staging of epithelial tumours and our overall understanding of malignant processes. Imaging techniques like radionuclide bone scan, magnetic resonance and computed tomography are usually inefective in detecting bone marrow metastases and bone marrow aspiration and biopsy remains the procedure of choice to document bone marrow involvement; It is the fastest, easiest and cheapest method to search for metastatic foci in the bone marrow [5,6] . With regard to detection techniques, most investigators have used immunocytochemical assays with a variety of ‘epithelial specifc’ cytoskeleton and membrane antigens. CK 7/20 have been found to be positive in most of the epithelial malignancy and hence shows great propensity for diferentiation of various epithelial malignancies [7,8] In this study, we are trying assess the prevalence of bone marrow metastases of epithelial malignancies coming to Akanksha Agarwal 1 *, Rashmi Kushwaha 1 , Wahid Ali 1 , Vijay Kumar 2 and Ashutosh Kumar 1 1 Department of Pathology, King George’s Medical University, Lucknow, UP, India 2 Department of Surgical Oncology, King George’s Medical University, Lucknow, UP, India ABSTRACT Background: Bone marrow is the most common site of metastases of epithelial malignancies from breast, lung, colon, prostate, ovaries and endometrium. These have poor prognosis as early tumor cells dissemination to bone marrow leads to poor treatment response. Bone marrow involvement by tumor cells can be seen on microscopic bone marrow examination and confrmed by immunohistochemistry. In this prospective observational study, we plan to analyze the incidence of bone marrow dissemination in epithelial malignancies and estimate the utility of immunohistochemistry in detecting micro metastases and correlate it with other clinicopathological parameters. Methods: clinical details and complete hematological workup was done in31 new cases of epithelial malignancies during our study period of one year. Bone marrow aspiration, bone marrow biopsy and clot section were done and analyzed morphologically and immunohistochemically using CK 7 and CK 20. Result: out of a total of 31 cases of epithelial malignancies, 2 cases of prostate carcinoma showed positive metastatic cell cluster and 2 cases of breast carcinoma and 1 case of lung carcinoma showed dispersed atypical cells in bone marrow. Conclusion: Immunohistochemistry did not show any observed beneft than routine microscopy in diagnosing the bone marrow metastases. Small sample size and lack of ancillary techniques like polymerase chain reaction(PCR) are drawback in the diagnosis of isolated tumor cells, micro metastases and confrmation of the results obtained on immunohistochemistry. Extensive studies are required to elucidate the pathogenetic pathway and clinical implications of bone marrow metastatic cells for the diagnosis, staging and treatment of epithelial malignancies. Keywords: Bone Marrow Metastases, Immunohistochemistry, Bone Marrow Examination, Epithelial Malignancies. DOI: 10.21276/APALM.1581