Ovarian Teratoma

OT are usually detected in young women; the patients' median age at diagnosis is 35 and 27 years in the case of mature cystic teratoma and immature teratoma, respectively [3] [6].

Abdominal pain is the single most important symptom of OT. Women may also experience abnormal uterine bleedings. Occasionally, OT exerts local mass effects that interfere with bladder and intestinal function. Torsion, rupture, and infection of OT are rare events, but dreaded complications causing a rapid deterioration of a patient's general condition [7]. Of note, about one in six patients are asymptomatic. Here, OT is incidental finding diagnosed during a routine physical and gynecological examination.

Workup comprises diagnostic imaging to confirm the presence of an ovarian mass and to assess whether metastases have developed in other parts of the reproductive system, lymph nodes, or distant organs:

• Ultrasonography yields reliable results regarding the presence of ovarian tumors and allows for the detection of metastases in other organs and lymph nodes. The ultrasonographic image of OT typically comprises hypo- and hyperechogenic areas, which correspond to heterogeneous tissues, calcified and fluid-filled spaces, and septa. This technique is readily available, cost-effective, and highly specific [8].
• Availability and costs argue against the employment of computed tomography and magnetic resonance imaging. They are, however, of major importance for tumor staging in the case of malignant OT. Additionally, these techniques may be helpful to clarify uncertain diagnoses [9], owing to a higher sensitivity (60-94% for ultrasonography, 93-98% for computed tomography, [8]).

In order to distinguish between benign and malignant OT, measurements of serum α-1-fetoprotein, β-human chorionic gonadotropin and cancer antigen 125 (CA 125) should be performed. Enhanced concentrations of either marker are indicative of malignancy [10] [11].

Ovarian teratoma (OT) is a germ cell tumor to be encountered in the female gonads. OT are rather common and account for up to 20% of ovarian neoplasms [1]. There are distinct types of OT [2]:

• Mature cystic teratoma is the most common type of OT. Tumor cells are well differentiated and derive from at least two of the three germ cell layers. A mature cystic teratoma typically consists of an outer layer of squamous epithelium enclosing fat, muscle, hair follicles, skin glands and liquid, sebaceous material. Therefore, this benign neoplasm is also referred to as a dermoid cyst. A considerable share of patients presents with bilateral tumors [3] [4]. Of note, mature cystic teratomas have occasionally been reported to undergo malignant transformation [5].
• Immature teratomas are similarly composed of tumor cells deriving from at least two germ cell layers. However, these cells are poorly differentiated and this type of OT is generally associated with higher tumor grades. Fortunately, less than 1% of OT are immature teratomas.
• Monodermal teratoma differs from the afore-described variants in that it contains degenerated cells of either ectodermal, mesodermal or endodermal origin only. Struma ovarii and ovarian carcinoid tumor fall into this category and primarily contain thyroid and neuroectodermal tissue, respectively. Other types of monodermal teratoma have been described.

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