Peripheral nerve sheath tumour mimicking deep calf thrombus: An incidental finding during lower limb venous Doppler ultrasound.

Introduction: Peripheral nerve sheath tumours are neurogenic neoplasms that arise from the nerve sheath which are not within the central nervous system. While most of these lesions may be benign, some of them may undergo malignant transformation, establishing why it is imperative for ultrasound practitioners to familiarise themselves with ultrasound presentations of this lesion to facilitate early and effective diagnosis, which would in turn positively impact patient management.

Case report: We present an incidental finding of a thrombus-mimicking peripheral nerve sheath tumour in a female patient who came to the ultrasound department for a left leg deep vein thrombosis scan.

Discussion: This case study demonstrates a peripheral nerve sheath tumour which by virtue of its location (very closely adjacent the deep calf veins) and appearance (incompressible, heterogeneous, minimal colour flow), mimicked a deep calf vein thrombus on ultrasound. Careful surveillance of the area on ultrasound revealed the lesion was distinct from the calf vasculature, and further imaging was advised. A magnetic resonance imaging was conducted confirming the diagnosis of a peripheral nerve sheath tumour.

Conclusion: In addition to assessing the lower limb venous system during deep venous thrombosis scans, sonographers should be mindful that other soft tissue lesions such as peripheral nerve sheath tumour may be present with symptoms that mimic those of a thrombotic leg, and therefore check to exclude or confirm the presence of any adjacent soft tissue lesions, especially at the symptomatic site indicated by the patient.