[Correlation of MRI features to histopathologic grade of soft tissue sarcoma].

BACKGROUND & OBJECTIVE Peripheral tumor growth pattern plays an important role in the local recurrence and metastases of soft tissue sarcoma. This study was to determine the peripheral growth pattern of soft tissue sarcoma by magnetic resonance imaging (MRI), explore its correlation to histological grade, and assess biological features of soft tissue sarcoma before operation. METHODS MRI was performed in 59 patients with soft tissue sarcoma. T1- and T2-weighted images were obtained using a spin-echo (SE) pulse sequence. Tumor margin, peritumoral high signal intensity sign and peritumoral low signal intensity capsule-like sign were evaluated on MR images. All patients were confirmed and graded by histopathology. RESULTS The histological grade of soft tissue sarcoma was closely related to the margin appearance (P<0.05): the margin was well defined in 60.0% grade I tumors, and poorly defined in 60.0% grade III tumors. No significant difference in the occurrence rates of peritumoral high signal intensity sign and peritumoral low signal intensity capsule-like sign was found between grade II and grade III tumors (P>0.05). The occurrence rate of peritumoral high signal intensity sign was significant lower and that of peritumoral low signal intensity capsule-like sign was significant higher in grade I tumors than in grade II-III tumors (10.0% vs. 74.4%, 80.0% vs. 15.4%, P<0.05). CONCLUSION The peripheral tumor growth pattern is related with histological grade, and may reflect the biological behaviors of soft tissue sarcoma.