Ultrasound Diagnosis of a Ganglion Cyst of the Long Head of the Biceps Tendon: A Case Report

Ganglion cysts are benign, fluid-filled masses that are commonly found in the spinoglenoid and suprascapular notches of the shoulder. However, they are seldom seen in proximity to the long head of the biceps tendon (LHBT). We introduce an exceptionally uncommon cause of severe shoulder discomfort: a ganglion cyst located within the joint of the LHBT, which was inadvertently identified as stemming from the bicipital groove. This unusual biceps tendon ganglion cyst was discovered during a routine ultrasound examination of the shoulder, characterized through ultrasonography, and later validated through arthroscopy. This case underscores the increasing importance for rheumatologists and physiatrists to familiarize themselves with bedside ultrasound and recognize its value as an enhancement to standard musculoskeletal assessments.