The leading causes of mediastinal lymphadenopathy are briefly described, and a clinical case is presented that demonstrates the difficulty of differential diagnosis of mediastinal lymphadenopathy in a patient with a nonspecific presentation. The unique feature of this case is the detection of granulomatous inflammation typical for tuberculosis in the intrathoracic lymph nodes with intact lung tissue and absence of specific bronchial and tracheal lesions, as well as no history and clinical signs of probable tuberculosis. Only histological examination of the lymph nodes was the key method for determining the diagnostic and treatment strategy.