<b>Diagnostic Accuracy of Magnetic Resonance Imaging in Detecting Malignancy in Musculoskeletal Tumors Taking Histopathology as Gold Standard</b>

Background: Musculoskeletal tumors represent a diagnostic challenge due to overlapping clinical and imaging features, while histopathology remains invasive and resource intensive. Magnetic resonance imaging (MRI), with its superior soft-tissue contrast and multiplanar capabilities, is widely used for characterization and surgical planning, yet variability in diagnostic performance necessitates further validation across diverse populations. Objective: To evaluate the diagnostic accuracy of MRI in detecting malignancy in musculoskeletal tumors, using histopathology as the reference standard. Methods: In this prospective diagnostic accuracy study conducted at a tertiary-care radiology department in Peshawar, Pakistan, from June to November 2024, 97 consecutive patients aged 18–70 years with clinically suspected musculoskeletal tumors underwent MRI on 1.5T or 3T scanners followed by histopathological confirmation. Predefined MRI signal and enhancement criteria were applied to classify tumors as malignant or non-malignant. Diagnostic indices were derived from 2×2 contingency tables, and subgroup analyses were performed across demographic and clinical variables in accordance with STARD recommendations. Results: Histopathology confirmed malignancy in 56 cases (57.7%). MRI achieved a sensitivity of 92.9% (95% CI: 82.7–98.0), specificity of 82.9% (95% CI: 67.9–92.9), positive predictive value of 88.1%, negative predictive value of 89.5%, and overall diagnostic accuracy of 88.7%. Diagnostic performance was consistent across age, sex, body mass index, residence, and occupational strata. Conclusion: MRI demonstrates high diagnostic accuracy for differentiating malignant from benign musculoskeletal tumors and can serve as a reliable non-invasive adjunct to histopathology in global oncology practice. These findings support the integration of MRI into diagnostic pathways to reduce unnecessary biopsies and guide surgical decision-making, while multicenter research incorporating advanced sequences is warranted to further improve specificity and generalizability.