Tuberculosis can occur in various organ systems and may present with diverse manifestations. We report an unusual case of mediastinal tuberculoma in a 3-month-old boy who presented to the hospital after experiencing fever, cough, and progressive pneumonia for two weeks. The chest computed tomography scan indicated a mediastinal mass suggesting lymphoma. However, histological analysis confirmed that the mass was caused by tuberculosis. The present report describes the delayed diagnosis of a disease due to an uncommon presentation. Misdiagnosing unusual cases of tuberculosis results in treatment delays and may lead to an increase in morbidity. Therefore, we suggest that tuberculosis should be included in the differential diagnosis for children presenting with a mediastinal mass, especially in areas with a high prevalence of tuberculosis.