A STUDY OF SOFT TISSUE TUMOURS' HISTOPATHOLOGY & CORRELATION OF HISTOLOGIC GRADE (FNCLCC SYSTEM) OF SARCOMAS WITH KI67 PROLIFERATIVE MARKER.

Soft tissue tumours encompass a diverse group of histomorphologically complex mesenchymal neoplasms. This eld remains expansive and underexplored. Accurate staging, crucial for patient treatment, involves histologic grading based on the FNCLCC system. Various methods assess proliferation activity, among which immunohistochemical (IHC) expression of the Ki67 marker is notably rapid and enhances routine histopathological examination (HPE) for diagnosis and grading. An observational study analyzed 120 STT specimens. Specimens underwent HPE after xation in 10% neutral buffered formalin, meticulous grossing, and preparation of FFPE blocks. FNCLCC grading categorized the tumours, and Ki67 antibody IHC staining assessed proliferative activity. STTs consti Results: tuted 4.2% of neoplasms during the study period, predominantly benign (69.2%), followed by malignant (23.3%) and intermediate (7.5%). Adipocytic tumors were most common (29.2%), followed closely by vascular tumours (18.3%). Most STTs were large (>5 cm), deep-seated, and painless. FNCLCC grading and Ki67 evaluation revealed low Ki67 indices predominantly in grade I sarcomas (25%), variable indices in grade II sarcomas (35.7%), and high indices in grade III sarcomas (39.3%). Statistically signicant correlations were observed between Ki67 score and tumour size (p = 0.04), Ki67 score and mitotic count (p = 0.03), and Ki67 index and FNCLCC grades (p = 0.0003). Pearson's coefcient indicated a strong positive correlation between grade and Ki67 score. This study demonstrates a positive correlation between FNCLCC grade and Ki67 score, Conclusion: suggesting that integrating Ki67 as a routine immunohistochemical marker could signicantly enhance tumour grading. This improvement is crucial for accurate staging, prognosis, and clinical outcomes in patients with STS.