A case of combined sarcoidosis and usual interstitial pneumonia.

Sarcoidosis is a systemic granulomatous disease of unknown etiology with characteristic pulmonary lesions, which are often distributed in the upper lung fields. We describe a unique case of sarcoidosis with lower lung field-dominant reticular shadows. Three years after the diagnosis of sarcoidosis based on histologic findings of the mediastinal lymph nodes and transbronchial lung biopsy specimens, the patient developed acute respiratory failure and died. The autopsy showed usual interstitial pneumonia (UIP), with honeycombing and superimposed diffuse alveolar damage of the lungs. The findings suggest that the patient had both sarcoidosis and UIP, and that the UIP later progressed to acute exacerbation.