The number of cases in the U.S. is estimated to be 10 to 40 per 100,000 people. Although the triggers for sarcoidosis are not yet known, scientists have figured out that the disease process is a result of abnormal white blood cell activation leading to a formation of granulomas in the tissues. When enough granulomas are formed within an organ, they may alter the normal architecture of the organ, causing the organ to function improperly. The symptoms of sarcoidosis are non-specific and will vary depending upon which part of the body is affected. The lung is the most commonly affected organ so respiratory symptoms such as cough, shortness of breath and a feeling of discomfort behind the sternum are widely seen.
Sarcoidosis is a difficult disease to diagnose.
Symptoms and routine physical exams usually give rise to the suspicion of sarcoidosis. Diagnosis of sarcoidosis is confirmed by a biopsy of the suspected granuloma, which is examined under the microscope. Common biopsy sites are the lungs and the lymph nodes. Chest X-ray and CT scans aid the doctor in locating the area of biopsy. Sarcoidosis is diagnosed only when the symptoms are consistent with a positive biopsy for the granuloma.