18-year-old woman • chest pain • shortness of breath • electrocardiogram abnormality • Dx?

THE CASE

An 18-year-old woman with no significant past medical history presented to the emergency department complaining of midsternal chest pain and mild shortness of breath, which had been intermittent for the past several months. She denied any history of deep vein thrombosis or pulmonary embolism risk factors, such as oral contraceptive use.

Laboratory values were within normal limits. An electrocardiogram (EKG), however, showed T-wave inversions in leads V₁ and V₂, and physical examination revealed decreased breath sounds in the right lung base. A chest radiograph and subsequent chest computed tomography (CT) were ordered.

The initial radiograph (FIGURE 1) showed a large right anterior mediastinal mass; the CT revealed fat, fluid, soft tissue, and ossification within the mass (FIGURE 2). The CT also showed evidence of local mass effect on the right atrium, as well as compressive atelectasis in the adjacent right lung, contributing to the patient’s EKG abnormality and physical exam findings.

THE DIAGNOSIS

Based on the patient’s clinical history and imaging findings, which were consistent with a benign well-differentiated teratoma, she was given a diagnosis of anterior mediastinal teratoma.

DISCUSSION

Teratomas are tumors composed of pluripotent stem cells that carry elements from all 3 of the embryologic layers (ectoderm, mesoderm, and endoderm).¹ There are 3 classifications of teratomas: mature (well-differentiated), immature (poorly differentiated), and malignant.

Tumors of germ cell origin are rare within the anterior mediastinum, accounting for 1% to 3% of total reported cases.² Among anterior mediastinal masses, germ cell tumors such as teratomas, seminomas, and nonseminomatous tumors comprise approximately 15% of adult and 24% of pediatric anterior mediastinal tumors.³

It is reported that up to 60% of patients with mediastinal teratomas present with no signs or symptoms upon diagnosis.⁴ When the mass is large, patients can develop chest pain or shortness of breath relating to tumor mass effect. In rare instances, there can be hemoptysis or trichoptysis, pathognomonic for teratomas with bronchial communication.⁵ Physical exam findings are also nonspecific and may include decreased breath sounds secondary to compressive atelectasis with large tumor burden.

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