Location: Anterior mediastinum.

Differential Diagnosis: Because of the calcifications and well-roundedness, the differential was narrowed down to teratoma (to include germ cell tumors) and was surgically confirmed.

Teratoma is the most common anterior mediastinal germ cell tumor. The incidence in males is equal to the incidence in females, and there is a bimodal age distribution (infancy and 20–40 year olds). The majority of patients are asymptomatic at the time of diagnosis.

•Teratoma Pathology

•Teratomas contain tissue from at least two primitive germ layers (endoderm, mesoderm, ectoderm).

•Approximately 50–75% have little to no malignant potential.

•Types of teratoma include mature, immature, and malignant.

•The treatment is typically surgical excision.

Middle Mediastinal Mass

The middle mediastinal region includes the following:

•Contains the pericardium and its contents, brachiocephalic vessels, ascending and transverse aorta, SVC and IVC, phrenic nerves, upper portion of vagus nerve, pulmonary arteries and veins, trachea and main bronchi, and their contiguous lymph nodes.

You can use the mnemonic LATTE to remember the following masses/conditions of the middle mediastinum. Although the esophagus is not in the middle mediastinum by definition, it is included for two reasons: esophageal tumors can extend into the middle mediastinum, and most importantly, it makes the mnemonic work!

L – Lymph nodes, metastasis

A – Aorta (and other vascular lesions)

T – Trachea, bronchi, bronchogenic cyst, inlet lesions

T – Tumor

E – Esophagus: carcinoma, hiatal hernia, duplication Cysts

The more specific differential of these anatomic regions includes the following:

•Lymph nodes

•Lymph node enlargement (most are malignant)

–Adenopathy

•Neoplastic adenopathy

•Inflammatory adenopathy

•Sarcoid; Castleman’s disease

•Inhalational Disease adenopathy