Diagnostic challenges in interstitial lung diseases using the example of microscopic usual interstitial pneumonia image in a patient with the clinical hypothesis of idiopathic pulmonary fibrosis - a case report.

Idiopathic pulmonary fibrosis (IPF) is the most common of the idiopathic interstitial pneumonias. The high-resolution tomography (HRCT) is highly recommended among patients with suspected IPF. Usual interstitial pneumonia (UIP) is the histopathological and radiological pattern of IPF. IPF is diagnosed if the appropriate combination of HRCT patterns and histopathological patterns are present.The authors present a case of a 49-years-old woman who was hospitalised due to the detection of a focal lesion in the left lung in an X-ray examination. A CT scan of the chest with contrast revealed a solid infiltration of the same area. The histopathology from a transbronchial lung biopsy from this abnormality showed microscopic honeycomb, fibroblast fibrosis, macrophage clusters loaded with hemosiderin and widened bronchioles - an image suggesting Usual Interstitial Pneumonia (UIP). Following that, a HRCT showed considerable differences in the lung image compared to the previous CT examination - no polycyclic lesion in the left lung was detected and the fibrous changes decreased. The patient had substantial formal features of UIP from the histopathological examination from TBLB. Therefore, there was a clinicalradiological discrepancy in the histopathology report. After a multidisciplinary consultation by renowned experts in pulmonology, radiology and histopathology, regardless of the patient's diagnostic path, the primary cause of the disease could not be determined. The analysis of this case strongly suggests that the histopathological examination alone is not sufficient in the diagnosis of IPF.