Small Subcutaneous Soft Tissue Tumors (<5 cm) Can Be Sarcomas and Contrast-Enhanced Ultrasound (CEUS) Is Useful to Identify Potentially Malignant Masses

Abstract

Subcutaneous masses smaller than 5 cm can be malignant, in contrast with the international guidelines. Ultrasound (US) and magnetic resonance imaging (MRI) are useful to distinguish a potentially malignant mass from the numerous benign soft tissue (ST) lesions. Contrast-enhanced ultrasound (CEUS) was applied in ST tumors, without distinguishing the subcutaneous from the deep lesions. We evaluated CEUS and MRI accuracy in comparison to histology in differentiating malignant from nonmalignant superficial ST masses, 50% smaller than 5 cm. Sensitivity, specificity, and positive and negative predictive values (PPV, NPV) with their 95% confidence intervals (CI) were calculated. Of malignant cases, 44.4% measured ≤5 cm. At univariate analysis, no statistically significant differences emerged between benign and malignant tumors in relation with clinical characteristics, except for relationship with the deep fascia (p = 0.048). MRI accuracy: sensitivity 52.8% (CI 37.0, 68.0), specificity 74.1% (CI 55.3, 86.8), PPV 73.1% (CI 53.9, 86.3), and NPV 54.1% (CI 38.4, 69.0). CEUS accuracy: sensitivity 75% (CI 58.9, 86.3), specificity 37% (CI 21.5, 55.8), PPV 61.4% (CI 46.6, 74.3), and NPV 52.6% (CI 31.7, 72.7). CEUS showed a sensitivity higher than MRI, whereas PPV and NPV were comparable. Also, masses measuring less than 5 cm can be malignant and referral criteria for centralization could be revised.

Contrast-enhanced ultrasound reveals perfusion differences between benign lipoma and semi-malignant atypical lipomatous tumors: A prospective clinical study

“…STTs were assigned to different perfusion patterns via a qualitative classification and differentiated between benign and malignant. Benign tumors showed no perfusion or homogeneous perfusion patterns, whereas malignant tumors often showed inhomogeneous and strong contrast enhancement with central areas of necrosis correlating with MRI imaging [13,15,16]. It could be demonstrated that CEUS can contribute to a faster and more precise STT assessment with high discrimination accuracy [15,17].…”

Not every knee tumour is a ganglion - retrospective analysis of benign and malign tumour entities around the knee

“…In soft tissue sarcomas, tumour size and location relative to the fascia are important for assessing malignancy risk [14]. While studies show that size ≥ 5 cm and increased age are main risk factors [7,15,32], even smaller lesions can be malignant [8], leading to recommendations for core needle biopsies in tumours ≥ 3 cm [23,31]. Importantly, in our study there was a relevant discrepancy of the suspected and the histopathologically-confirmed diagnosis, which in 6 cases lead to a malignant tumour diagnosis of a mass primarily considered benign (2.1% of total true tumours).…”

Nanoscale Contrast Agents for Ultrasound Imaging of Musculoskeletal System

“…In addition, quantitative CEUS allows precise assessment of microcirculatory perfusion, as a surrogate parameter for tissue viability and metabolism, and objectively monitoring the progression of postoperative microcirculatory changes. Furthermore, CEUS is also expected to be an additional diagnostic tool for predicting the malignant potential of bone tumors, due to varying enhancement patterns [ 51 ]. Hence, CEUS not only allows for early identification and initial treatment of patients with related injuries but is also expected to be used to monitor the process of blood flow reconstruction, thus facilitating the postoperative rehabilitation of patients.…”