A woman with a swelling in her neck

: A 55-year-old woman presents with a progressive swelling in the suprasternal notch. Ultrasound and CT-scan show a cyst filled with remarkably uniform nodules of fat density. This radiological presentation is known as the sack of marbles sign and is pathognomonic for dermoid cysts. Dermoid cysts are congenital and usually benign germ cell tumors.