Snapshot A 20-year-old G1P0 woman presents to clinic with 3 months of lower left quadrant pain. Her menstrual cycle is regular and occuring every 30 days. She uses a copper IUD for contraception which was placed 2 years ago. She has no significant medical or surgical history. Her temperature is 98.6°F (37.0°C), blood pressure is 118/78 mmHg, pulse is 65/min, and respirations are 16/min. Pelvic exam is positive for left adnexal fullness. A urine β-hCG test is negative and a transvaginal ultrasound demonstrates a 3.5 cm hypoechogenic cystic mass with calcifications. The patient's mass is removed surgically and she diagnosed with a mature cystic teratoma. A photograph of the removed lesion is taken. Introduction Overview teratomas are germ cell tumors most often benign that can contain tissue from all 3 different germ cell layers treatment usually involves surgery and possibly chemotherapy depending on whether the tumor is malignant or not Epidemiology incidence most common germ cell tumor approximately 15% of ovarian neoplasms are teratomas demographics women aged 10-30 years of age location mostly in ovaries teratomas can also be found in testis, mediastinum, cranium, and sacrococcygeal area risk factors for malignant transformation age ≥ 45 years of age tumor diameter ≥ 10 cm rapid tumor growth Pathogenesis failure of complete migration of pluripotent stem cells during embryogenesis should normally migrate from yolk sac endoderm to urogenital ridge Prognosis most are benign 2% become malignant Classification Ovarian Teratomas Types and Features Type Prevalence Histopathology Potential for Malignancy Mature (dermoid) 95% of ovarian teratomas Differentiated tissue ectodermal mesodermal endodermal Hair, teeth, and sebaceous glands Cystic Most are benign 0.2-2% malignant transformation Immature < 1% of ovarian teratomas Immature and mature tissue ectodermal mesodermal endodermal High potential for malignancy Over 1/3 of all malignant ovarian germ cell tumors Monodermal Uncommon Specialized and mature cell types struma ovarii (thyroid tissue) can cause clinical hyperthyroidism carinoid tumors neural differentiation Most are benign Presentation Symptoms common symptoms pain location lower abdomen severity often asymptomatic depends on tumor size Physical exam inspection visible masses may be seen swelling of tailbone in newborn motion tumor may be palpable Imaging Ultrasound indications suspected ovarian mass views transvaginal findings hyerechoic areas fluid-fluid levels bright echoes shadowing echo densities sensitivity and specificity sensitivity ~85% specificity ~98% CT indications adjunct to ultrasound surgical planning findings complex septa internal debris fat attenuation calcification Studies Serum labs AFP LDH β-hCG Urine labs β-hCG Invasive studies Histology immunohistochemistry Differential Ectopic pregnancy key distinguishing factor positive urine β-hCG test Ovarian adenocarcinoma key distinguishing factors typically older age of onset fatigue bloating and lack of appetite more solid appearance on ultrasound Treatment Medical chemotherapy indications malignancy Surgical ovarian cystectomy indications all patients with teratomas and future childbearing plans salpingo-oopherectomy indications those who do not want to bear further children Complications Ovarian torsion incidence 5-15% of patients with teratomas experience ovarian torsion risk factors ovarian masses long ovarian ligaments pregnancy tubal ligation treatment surgery Cyst rupture incidence rare 0.3-2.5% risk factors pregnancy torsion trauma Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis incidence almost 60% of patients with anti-NMDA receptor encephalitis have ovarian teratomas risk factors neural components in teratoma