INTRODUCTION: Our report shows a rare case of suprascapular nerve palsy due to a SLAP-related ganglion cyst resulting in isolated weakness of the infraspinatus muscle. CASE REPORT: We report on a 31-year old volleyball player with severe shoulder pain. A ganglion cyst was excised in an open procedure and was completely resolved in a postoperative magnetic resonance imaging (MRI). But the patient again had pain and disability 7 months after this procedure. A renewed MRI scan showed a cystic mass in the spinoglenoid notch. An electromyography revealed an isolated lesion of the suprascapular nerve. The patient was treated by shoulder arthroscopy with refixation of a type-II-SLAP-lesion and drainage of the cyst formation. At latest follow-up 29 months after surgery, the patient's pain and shoulder function improved with a constant score of 94 points. A MRI scan documented complete cyst resolution. CONCLUSIONS: Treatment options for ganglion cysts at the spinoglenoid notch are various and can be handled in conservative and operative ways. We believe that the arthroscopic concept with the management of a SLAP lesion as the cause of cyst formation, and the drainage of the ganglion is an effective way with low surgical morbidity that shows good postoperative results.