Thymic Epithelial Neoplasm

Thymic epithelial neoplasms (TEN) are rare malignancies arising from the epithelium of the thymic gland. They comprise three sub-types: thymoma, thymic carcinoma, and thymic neuroendocrine carcinoma (see these terms).

Epidemiology

TENs have an annual incidence of approximately 1/588,000. Thymoma is the most frequent subtype, while thymic carcinoma and thymic neuroendocrine carcinoma represent 1% and 2-4% of the anterior mediastinal tumors, respectively. The two latter have a higher malignant potential than thymoma. TENs usually occur in adults from 30 to 80 years of age, with a median age of 60 years, but they can also occur during childhood.

Clinical description

Most adult patients are asymptomatic, while in children nearly two thirds present with symptoms that include cough, chest pain, weight loss, fatigue and dyspnea. Many autoimmune syndromes are associated with TENs. Myasthenia gravis (see this term) is observed in 30-50% of thymoma cases. Phrenic nerve palsy and superior vena cava syndrome are usually observed in cases of thymic carcinoma.

Etiology

Etiology is unknown.