"The Terrible Ts" That Was Not: Anterior Mediastinal Tuberculosis Mimicking Malignancy in an Immunocompetent Young Adult

Anterior mediastinal masses are typically approached through the classic "terrible Ts" differential (thymic tumors, lymphoma, germ cell tumors, and thyroid disease). Tuberculosis (TB) rarely presents as an isolated anterior mediastinal mass in an immunocompetent adult and can mimic malignancy. We report the case of a male patient in his late 20s who presented with a two-month persistent dry cough, low-grade fever, and 8 kg of unintentional weight loss. Initial chest radiography demonstrated mediastinal widening, and high-resolution computed tomography (HRCT) revealed a large lobulated anterior mediastinal mass with central necrosis measuring 85 × 67 mm, abutting the pericardium and aortic arch, with subcarinal lymphadenopathy. Serum alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (β-hCG) were within normal limits (AFP: 3.59 ng/ml (reference range: 0.89-8.78); β-hCG: 1.50 mIU/ml (reference range: