Dermoid cysts of the ovary account for 20% of ovarian neoplasms.
These are benign germ cell tumours composed of tissues derived from two of the three germ cell layers (ectoderm, endoderm, and mesoderm) like tooth, hair, sebaceous secretions, thyroid tissue etc.
Most of the dermoid cysts are silent and are incidentally detected; however some may be symptomatic due to large size resulting in compression of adjacent structures. Torsion or rupture
Characteristic sonographic appearances include
Focal or diffuse hyper echoic component
Areas of acoustic shadowing also known as “the tip of the iceberg “sign.
Echogenic lines and dots also referred to as “the tip of the iceberg” sign. Rokitansky Nodule (hyper echoic component) corresponds to mixed hair and sebaceous material or calcification or bone or tooth.
Floating Echogenic Globules within a large mass is an uncommon appearance.
Dermoid cysts of size >4 cm needs to be surgically removed for the risk of torsion.