Introduction: Pseudoaneurysms are abnormal arterial aneurysmal sacs contained by only the tunica adventitia and/or surrounding soft tissues and may mimic soft tissue tumours both clinically and radiologically. Several overlapping features may exist: anatomic location close to a neurovascular bundle, haemorrhagic components, heterogeneous signal intensity on magnetic resonance imaging (MRI) and a history of a painless, slow growing mass. A key differentiating factor is the pulsation artefact, or ‘ghosting’ artefact, on MRI owing to sufficiently high velocity flow in a pseudoaneurysm, as well as the ‘ying-yang’ duplex ultrasound appearance of blood flow ‘to-and-fro’ within the sac. Case details: This case report is of a male in his 60s who was referred to our institution for a soft tissue sarcoma and potential biopsy. He was eventually diagnosed with a large posterior tibial artery pseudoaneurysm and biopsy was not performed. We present the multi-modality imaging findings used to make this diagnosis and discuss useful radiological features to distinguish vascular from soft tissue tumours. Conclusion: The case highlights the importance of considering vascular lesions in sarcoma care to avoid iatrogenic injury, which may be catastrophic. This is the second reported case of a pseudoaneurysm mimicking a soft tissue neoplasm in this location.
Mirza et al. (Sun,) studied this question.