Aspiration of a Large Acromioclavicular Joint Cyst Complicated by Recurrence and Enlargement: A Case Report.

This case report describes a patient with an enlarging and painless lump over the right acromioclavicular joint (ACJ). MRI showed a synovial cyst superior to the ACJ with a concomitant full-thickness tear of the supraspinatus. The patient underwent needle aspiration of the lump, which yielded 100ml of gelatinous fluid with no microbe growth. Despite repeated aspirations, the ACJ cyst continually enlarged beyond its initial size. This case report describes an ACJ cyst that enlarged in size after needle aspiration. The authors suggest surgical alternatives if cyst recurrence is observed after the initial attempt of aspiration.