CLINICOPATHOLOGICAL STUDY OF SOFT TISSUE TUMORS AND IMMUNOHISTOCHEMICAL ANALYSIS

Background: Soft tissue tumors (STTs) comprise a heterogeneous group of mesenchymal neoplasms with overlapping clinical and histological features. Accurate diagnosis often requires correlation of morphology with immunohistochemistry (IHC).

Objectives: To study the clinicopathological spectrum of soft tissue tumors and to evaluate the diagnostic utility of immunohistochemical analysis.

Methods: A prospective observational study of 80 soft tissue tumor cases was conducted over one year. Clinical data, gross findings, histopathology, and IHC markers—including vimentin, SMA, desmin, S-100, CD34, CD31, cytokeratin, EMA, myogenin, MyoD1, and TLE-1—were evaluated. IHC was performed in morphologically ambiguous and malignant cases.

Results: Of the 80 cases, 52 (65%) were benign, 4 (5%) intermediate, and 24 (30%) malignant. The lower extremity was the most common site (35%). Lipoma was the predominant benign tumor, while Undifferentiated Pleomorphic Sarcoma was the most common malignant tumor. Malignant tumors showed significantly larger size and occurred at a higher mean age compared to benign tumors (p < 0.05). Diagnostic accuracy improved markedly from 61% (pre-IHC) to 95% (post-IHC) (p < 0.001, McNemar). IHC markers showed strong lineage-specific positivity, notably S-100 in schwannoma, TLE-1 in synovial sarcoma, Myogenin/MyoD1 in rhabdomyosarcoma, and CD31/CD34 in angiosarcoma.

Conclusion: Soft tissue tumors demonstrate wide morphological diversity. While histopathology remains the primary diagnostic tool, IHC is essential for accurate classification, particularly in spindle cell, pleomorphic, and small round cell tumors. A combined clinicopathological and immunohistochemical approach markedly enhances diagnostic precision and guides appropriate patient management.