An unusual sonographic appearance of a dermoid cyst in a young patient

A dermoid cyst is a rare benign cystic teratoma. On ultrasound, it has variable sonographic features since it is usually filled with an admixture of ectoderm, mesoderm, and endoderm origin contents. Because of the lumen of the dermoid cyst is usually filled with an admixture of ectoderm, mesoderm and endoderm origin contents, it appears as different areas of echogenicity. The coalescence of the hyperechoic fat into globules within the hypoechoic fluid matrix forming an unusual appearance of ''Coins-in-Sack'' on ultrasonography. This is virtually typical for a dermoid cyst. In this case, we suggested the term "Coins-in-Sack" appearance as an accurate and descriptive diagnostic sonographic feature of this an uncommon para-sacral dermoid cyst.