To determine the incidence and characteristics of extravascular masses (EVM) giving rise to symptoms and signs of deep venous thrombosis (DVT).Design and technique:
Routine ultrasound colour duplex scanning during a 6-month period.Patients:
Three hundred and two inpatients and outpatients investigated on suspicion of DVT.Setting:
Department of Clinical Physiology, which is the central non-invasive diagnostic unit of the county.Results:
A diagnostis of DVT was made in 33%. EVM were detected in 14 patients (5%). In most cases the characteristic appearance on scanning was spindle-shaped (like a ‘mouse’) and mostly confined to the upper calf. These EVM were regarded as intramuscular haematoma or ruptured popliteal cysts.Conclusion:
EVM of the leg are (1) a frequent cause of ‘pseudothrombosis' and can positively be identified by duplex ultrasound scanning: (2) most frequently found in the medial aspect of the right calf; and (3) often detected in patients with rheumatoid arthritis or patients on anticoagulant therapy and may give rise to signs and symptoms identical to DVT.