Symptomatic humeral head cysts are rare and only few cases need a surgical intervention. This article describes the case of a 20-year-old male patient with a symptomatic cystic lesion of the humeral head. Based on the radiologically confirmed diagnosis and persisting pain over the posterior humeral head, the indications for arthroscopy and filling of the cyst by spongiosaplasty were fulfilled. Immediately following surgery the symptoms improved and 6 weeks after the intervention the patient was free from pain.