Unique Location of a Ganglion Cyst Following Shoulder Arthroscopy: A Case Report

Introduction: Ganglion cyst formation following shoulder arthroscopy is an exceptionally rare complication, particularly when arising from an arthroscopy portal site. Most shoulder ganglion cysts are associated with labral pathology and are typically located in the spinoglenoid or suprascapular notch. Portal-site or periarticular cysts cause a diagnostic challenge and are seldom reported in the literature. Case Report: We present the case of a 56-year-old female with a history of multiple prior shoulder arthroscopic procedures who developed a painful, localized swelling at the lateral arthroscopy portal site 8 weeks after surgery. Initial post-operative recovery was uneventful. Imaging studies revealed a well-defined cystic lesion without communication with the glenohumeral joint. Laboratory evaluation showed no evidence of infection. Due to persistent symptoms, surgical excision was performed. Intraoperatively, the cyst was found to originate from the periportal region without a clear intra-articular connection. Histopathological examination confirmed the diagnosis of a ganglion cyst. The patient experienced complete symptom resolution with no recurrence at 2-year follow-up. Conclusion: This case highlights a rare post-operative complication of shoulder arthroscopy and emphasizes the importance of considering periportal ganglion cysts in patients presenting with delayed post-operative swelling or pain. Awareness of this entity allows timely diagnosis and definitive treatment with excellent clinical outcomes.