Ultrasound Diagnosis of a Pseudotumor Secondary to a Partial Thickness Distal Biceps Tear Resulting in Pronator Syndrome: A Case Report

Abstract

A 53-year-old right-handed female weightlifter presented to our clinic for evaluation of left elbow pain and intermittent numbness in her first 3 digits. She reported an elbow injury while weight lifting and carrying heavy planters 6 months earlier. A magnetic resonance imaging obtained previously was interpreted as bicipital-radial bursitis, and she had previously undergone a comprehensive nonoperative management program for her pain and numbness. A diagnostic ultrasound performed in clinic revealed distal biceps tendinopathy, bicipital-radial bursitis, and "pseudotumor," which was dynamically compressed between the biceps tendon and radius with pronation and also caused a mass effect on the median nerve at the level of the pronator teres. Surgical excision of the mass resulted in near-complete resolution of her symptoms, and histology was consistent with scar tissue. This is the first case to the best of our knowledge to describe point-of-care ultrasound diagnosis of a biceps tendon "pseudotumor," as well as demonstrating dynamic impingement of this pseudotumor causing mass effect on the median nerve.