Teratoma, ovarian

Teratoma, ovarian: Tumor that develops from a totipotential germ cell (a primary oocyte) retained within the egg sac (ovary). Being totipotential, that cell can give rise to all orders of cells necessary to form mature tissues and often recognizable structures such as hair, bone and sebaceous (oily) material, neural tissue and teeth. These tumors may occur at any age but the prime age of detection is in the childbearing years. The average age is 30. Up to 15% of women with ovarian teratomas have them in both ovaries. The tumors can range in size from a centimeter (less than a half inch) up to 45 cm (17 inches) in diameter. They can cause the ovary to twist (torsion) and imperil its blood supply. Although the large majority (about 98%) of ovarian teratomas are benign, the remaining fraction (about 2%) becomes malignant. The larger the ovarian teratoma, the greater the risk of rupture with spillage of the greasy contents which can create problems with adhesions, pain etc. Removal is usually the treatment of choice by laparotomy (surgery) or laparoscopy (with a scope). Ovarian teratomas are also called dermoid cysts of the ovary and referred to simply as dermoids.