The pitfalls of ultrasonography in the evaluation of soft tissue masses

Abstract

Ultrasonography is associated with a high error rate in the evaluation of soft tissue masses. The purposes of this study were to examine the nature of the diagnostic errors and to identify areas in which reporting could be improved. Patients who had soft tissue tumours and received ultrasonography during a 10-year period (1999-2009) were identified from a local tumour registry. The sonographic and pathological diagnoses were categorised as either 'benign' or 'non-benign'. The accuracy of ultrasonography was assessed by correlating the sonographic with the pathological diagnostic categories. Recommendations from radiologists, where offered, were assessed for their appropriateness in the context of the pathological diagnosis. One hundred seventy-five patients received ultrasonography, of which 60 had 'non-benign' lesions and 115 had 'benign' lesions. Ultrasonography correctly diagnosed 35 and incorrectly diagnosed seven of the 60 'non-benign' cases, and did not suggest a diagnosis in 18 cases. Most of the diagnostic errors related to misdiagnosing soft tissue tumours as haematomas (four out of seven). Recommendations for further management were offered by the radiologists in 144 cases, of which 52 had 'non-benign' pathology. There were eight 'non-benign' cases where no recommendation was offered, and the sonographic diagnosis was either incorrect or unavailable. Ultrasonography lacks accuracy in the evaluation of soft tissue masses. Ongoing education is required to improve awareness of the limitations with its use. These limitations should be highlighted to the referrers, especially those who do not have specific training in this area.