Here are bilateral mature cystic teratomas of the ovaries. These tumors represent one form of ovarian germ cell tumor. A variety of mature, well-differentiated tissue elements may be found from all three embryologic germ layers (ectoderm, mesoderm, endoderm). These tumors are often called "dermoid cysts" because they are mostly cystic and mostly contain ectodermal elements, typically resulting in the abundant hair seen here.