157 Mature Teratoma

Clinical Presentation

74-year-old woman with cough and chest pain

Radiologic Findings

PA (Fig. 157.1) and lateral (Fig. 157.2) chest radiographs demonstrate a large left anterior mediastinal mass with a thin peripheral rim of curvilinear calcification. Unenhanced chest CT (mediastinal window) (Figs. 157.3, 157.4) shows a heterogeneous spherical mass in the left lobe of the thymus. Note the peripheral curvilinear calcification and internal areas of soft tissue, fluid, and fat attenuation.

Diagnosis

Mature Teratoma

Differential Diagnosis

None

Discussion

Background

Germ cell neoplasms typically occur in the gonad but may also affect extragonadal sites, usually the anterior mediastinum (near or within the thymus). Mature teratoma is a benign neoplasm that accounts for approximately 70% of all primary mediastinal germ cell neoplasms.

Fig. 157.1

Fig. 157.2

Fig. 157.3

Fig. 157.4

Etiology

The etiology of germ cell neoplasms is poorly understood. It is theorized that extragonadal mature teratomas may arise from primitive germ cells that are “misplaced” along midline structures during their embryologic migration from the yolk sac to the gonad.

Clinical Findings

Patients with mature teratoma are typically children and young adults (usually under 40 years of age). Patients may be asymptomatic or may present with signs and symptoms of compression of adjacent structures, including chest pain, dyspnea, and cough, or because of symptoms related to tumor rupture.