A – 19 year – old men was reffered to our Surgical department with a 4 – month history of an asymptomatic swelling in the left supraclavicular fossa. The patient a few months ago, carried sacks of cement. The left supraclavicular fossa was enlarged by a clearly delineated, elastic fluctuating swelling with a diameter of 10-12 cm, spreading infraclaviculary. The ultrasound examination confirmed an infraclIavicular spreading and revealed a hypoechogenic echo-free mass of the size of 10x15 cm, clearly outlined and no internal perfusion was found by color-coded Doppler investigation. The blood count and biochemical tests were normal. The histologically examination was found the presence of a tissue characteristic for a synovial cyst and a diagnosis of acromioclavicular cyst was made. Treatment of synovial cysts was surgical with surgical resection of the cyst.