Dear Readers,

the current issue of „Progress in Medicine” is in part dedicated to the selected pulmonary diseases which are not as common as pneumonia, asthma or chronic obstructive pulmonary disease. The less prevalent diseases are less known to doctors and are more difficult to diagnose not only by primary care physicians but also by internal medicine specialists or pulmonologists. The goal of the presented series of articles is to give the readers the concise information on the symptomatology and diagnostics of some rare pulmonary diseases.

In diagnosing sarcoidosis, finding of non-caseating granulomas in the microscopic examination of tissue sample with simultaneous exclusion of tuberculosis by the microbiological means, plays pivotal role. Besides microbiology methods, tuberculin skin test is also used. It is simple and easily available. However, it has many disadvantages, which are discussed in one of the articles.