• Germ cell ovarian tumors
  • Arise from the primordial germ cells (e.g., oocytes)

Dermoid cysts (mature cystic teratoma)

---

Epidemiology

• Most common of all germ cell tumors (90% of all cases)
• Most common ovarian tumor in women < 30 years

Clinical features

• Mostly asymptomatic
• Larger tumors may cause:
  • ↑ Abdominal girth
  • Pressure symptoms (e.g., ↑ urinary frequency)
  • Lower abdominal pain

Diagnostics

Ultrasound appearance

• Heterogeneous mass
• Hyperechoic nodule
• Echogenic shadowing
• Absent internal vascularity and/or fluid-fluid levels

Histology

• Contains somatic tissue (e.g., hair, teeth, sebaceous glands) from any of the three embryonic germ layers:
  • Endoderm
  • Mesoderm
  • Ectoderm