Our experience in soft tissue tumours in correlation with Immunohistochemistry: A retrospective study

Introduction: The diagnosis and classification of soft tissue sarcomas has been a source of difficulty for surgical pathologists. This has been largely attributable to a significant degree of overlap in histologic features among different types of soft tissue sarcomas. The immunohistochemical identification of various cell and tissue markers specific for certain avenues of cell differentiation has permitted more accurate diagnosis and classification of these tumors. Objective: The objective of this study was to evaluate soft tissue tumors which were unclassified on histopathology by IHC for typing the cell lineage. Materials and Methods: We evaluated 61 cases of soft tissue tumours reported in a period of three years from April 2013 to March 2016 in which histopathology was inconclusive and IHC proved to be useful to reach to a definite diagnosis. Conclusion: In our study, IHC contributed to the diagnosis in 80.3% cases where it helped to determine the soft tissue lineage. It was noncontributory in 13.1% cases where even after IHC the lineage could not be determined. In 6.6% cases the final diagnosis given after IHC was not correlating with the histopathological diagnosis. Hence we conclude that only histopathological examination is not sufficient at all times because there is a morphologic overlap of soft tissue sarcomas with each other and with some carcinomas and melanomas. Though immunohistochemistry is not a substitute for histopathological examination, it acts as an adjunct to arrive at definite diagnosis and hence proves to be the most important ancillary technique in the diagnosis of soft tissue tumors. Keywords: Soft tissue tumors, Immunohistochemistry, Cell lineage, Hematoxylin and eosin, Diagnosis