Lymphoepithelioma-like carcinoma (LELC) of the thymus is a primary thymic carcinoma characterized by a syncytial growth of undifferentiated carcinoma cells accompanied by a lymphoplasmacytic infiltration similar to undifferentiated carcinoma of the nasopharynx.^1,2,3,4 Although a requirement for LELC of the lung, thymic LELC may or may not be associated with Epstein-Barr virus (EBV). Thymic LELC presumably arises from thymic epithelial cells.⁵

Thymic LELC is a rare tumor. It represents from 4% to 6% of thymic carcinomas.^{6,7,8,9,10,11,12}

Thymic LELC occurs twice more commonly in male than female patients.⁵ The patient’s age ranges from 4 to 76 years with a median of 41 years.⁵

Patients typically present with signs and symptoms caused by compression of mediastinal organs, but some patients are asymptomatic and incidentally found to have an anterior mediastinal mass upon
imaging examination. Superior vena cava syndrome is seen in patients with more advanced disease.¹³ There is no association with myasthenia gravis, but polymyositis, nephritic syndrome, and hypertrophic pulmonary osteoarthropathy have been reported.^1,2,14