Does size reliably predict malignancy in soft tissue tumours?

In this retrospective study we examined whether size is a viable marker of tumour malignancy in soft tissue masses (STM) and if the ratio of width and length (R-ALD) of an STM reflects tumour biology more accurately. Measurements of maximal lesion size and perpendicular diameter were performed in available MRI and ultrasonography studies of 212 patients (mean age 54.4 +/- 17.2 years, male:female 1:1.12) with a histologically verified diagnosis. Overall, 28.2 % of lesions were malignant, 11.1 % intermediate, and 58.8 % benign. Size alone was a weak predictor of malignancy in STMs (sensitivity 68.8 %, specificity 50.3 %, positive predictive value [PPV] 44.0 %, negative predictive value [NPV] 80.4 %). R-ALD showed better discriminatory power with greater separation between benign and malignant entities and higher values for sensitivity (83.6 %), specificity (53.6 %), and NPV (89.0 %). A weighted combination of size, age and R-ALD improved diagnostic power, demonstrating higher values for sensitivity (77.0 %), specificity (80.1 %), PPV (61.0 %), and NPV (89.6 %). Size should not be used alone to estimate an STM's malignancy. R-ALD better reflects a lesion's growth pattern and a combination of age, size, and R-ALD helps to discriminate more accurately between benign, intermediate, and malignant entities. These findings should help to estimate easily whether a newly found STM is benign or malignant prior to further workup. aEuro cent Size does not reliably differentiate between benign, intermediate, and malignant tumours aEuro cent The R (ALD) (ratio of lateral to axial diameter) improves diagnostic confidence aEuro cent When combined with age and size, STM differentiation was further enhanced aEuro cent These measurements can aid in earlier detection of sarcomas.