Diagnosis of mediastinal tuberculosis: two clinical cases of patients coming from Pakistan

Tuberculosis (TB) is a common disease in Pakistan with 18 % of extra-pulmonary cases. Pakistan ranks fourth amongst high burden countries for TB in the world. Mediastinal involvement is rare in particular in the forms of lymphadenitis without lung damaging. The typology of the migration flows has modified the tuberculosis’ epidemiological distribution and the number of the extrapulmonary cases are increasing in Europe and in Italy. Diagnosis of mediastinal tuberculosis is difficult as the clinical presentation lacks specificity, imaging studies do not provide conclusive information and the differential diagnosis is a common challenge in clinical practice. The suspect of tuberculosis must be considered including acid-fast bacilli (AFB) staining (Ziehl-Nielsen and auramine), cultures and nucleic acid technology methods. We report two cases of mediastinal tuberculosis without a pulmonary tuberculosis in immunocompetent patients. This last condition, makes our cases even more rare. The first case is a man of 48-years-old presented with syncope, arrhythmia and weight loss of 20 kg during the last four months. The second case is a man of 29-years-old presented with fever (102 °F), dry cough and nocturnal sweating. The process that lead to the diagnosis of mediastinal tuberculosis, particularly in immunocompetent patients and without a concurrent diagnosis of pulmonary tuberculosis, is difficult to implement in a general clinical practice. These cases require a close examination of the differential diagnosis and the different and complex clinical pictures related to Mycobacterium tuberculosis must not be excluded. Moreover, it is needed to adopt and coordinate both mini-invasive diagnostic systems (e.g. Endobronchial ultrasound-guided transbronchial needle aspiration, EBUS-TBNA) and mycobacterial tests (microscopy, cultures and nucleic acid amplification techniques, NAAT) able to confirm or exclude the diagnosis of tuberculosis with an acceptable precision. Our cases demonstrated the key role of mycobacterial cultures in the diagnosis of these rare forms of mediastinal tuberculosis.