Congenital unilateral absence of the long head of the biceps tendon: A diagnostic challenge in shoulder pain evaluation

Chronic shoulder pain is a common clinical complaint, frequently linked to adhesive capsulitis or rotator cuff disease. We describe a rare instance of a 52-year-old man who was initially diagnosed with adhesive capsulitis after he presented with recurrent right shoulder pain and limited mobility. However, congenital absence of the long head of the biceps tendon (LHBT) with intact rotator cuff structures was identified by magnetic resonance imaging. Very few occurrences of LHBT agenesis have been documented in the literature, making it a rare anatomical variation. It can cause difficulties in diagnosis by mimicking more common shoulder problems. To avoid incorrect diagnosis and improper treatment, accurate identification using imaging is essential.