Jiwoo Park, Sang Kyum Kim, Seung Hyun Kim, Seok Hahn, Young Han Lee
SWE-derived stiffness appears to be affected by intratumoral heterogeneity, particularly microscopic necrosis, which may help explain its nonlinear relationship with histologic grade. Although SWE alone showed limited sensitivity for sarcoma discrimination, its relatively high specificity may complement conventional US when markedly elevated stiffness is present.
PURPOSE: This study aimed to evaluate shear-wave elastography (SWE)-derived stiffness values and key histopathologic features of soft-tissue sarcomas and to assess the potential diagnostic value of SWE for differentiating sarcomas from non-sarcoma soft-tissue lesions.
METHODS: This retrospective study included 49 consecutive patients with clinically suspected soft-tissue tumors who underwent conventional ultrasonography (US) and SWE between April 2024 and March 2025. Quantitative SWE parameters, including mean and maximum stiffness values in kilopascals, were measured from at least four acquisitions for each lesion. Histopathologic grade was determined using the Fédération Nationale des Centres de Lutte Contre le Cancer (FNCLCC) system, and key histopathologic features relevant to SWE interpretation were assessed, including tumor necrosis, mitotic count, cellularity, and extent of myxoid stroma. Associations between SWE-derived stiffness values and histopathologic features were evaluated as the primary analysis, and diagnostic performance for sarcoma discrimination was evaluated as a secondary analysis. A P<0.05 was considered to indicate statistical significance.
RESULTS: Microscopic necrosis was the only histopathologic feature significantly associated with SWE-derived stiffness; sarcomas without necrosis showed higher stiffness values than those with necrosis (P<0.05). SWE stiffness values showed a nonlinear relationship with FNCLCC grade, increasing from grade 1 to grade 2 and then decreasing in grade 3 sarcomas. Conventional US showed high sensitivity (84.4%) but low specificity (35.3%) for sarcoma discrimination, whereas SWE-derived stiffness showed low sensitivity (21.9%-31.3%) but relatively high specificity (82.4%-88.2%).
CONCLUSION: SWE-derived stiffness appears to be affected by intratumoral heterogeneity, particularly microscopic necrosis, which may help explain its nonlinear relationship with histologic grade. Although SWE alone showed limited sensitivity for sarcoma discrimination, its relatively high specificity may complement conventional US when markedly elevated stiffness is present.