Background <p>Mediastinal lipomas are rare benign tumors, the size and location of the tumor presented a diagnostic challenge, as large mediastinal masses can compress adjacent structures, leading to symptoms such as dyspnea, chest pain, or cough. However, our patient remained asymptomatic, and the mass was discovered incidentally during a routine health examination.</p> Case presentation <p>We report a case of giant mediastinal lipoma discovered incidentally in a young asymptomatic male. In this case, we report an unusually large mediastinal lipoma measuring approximately 11.7 × 6.3&#xa0;cm in an 18-year-old asymptomatic male.</p> Conclusions <p>We present the first reported case of a giant mediastinal lipoma that was discovered incidentally in an asymptomatic adolescent.</p>