Diagnosis of pulmonary sarcoidosis comorbid with non-specific interstitial pneumonia: a case report.

Background: Although the imaging manifestations of pulmonary sarcoidosis have been described in detail in previous studies, a consensus has not been reached on the imaging presentation of non-specific interstitial pneumonia (NSIP) lookalike pattern as a distinct pattern in the diagnosis of pulmonary sarcoidosis in high-resolution computed tomography (HRCT). No cases of pulmonary sarcoidosis comorbid with NSIP have been reported.

Case presentation: A 53-year-old male presented to the hospital with a five-year history of recurrent coughing up sputum and a four-year history of shortness of breath. In addition to the typical features of pulmonary sarcoidosis, the patient's HRCT also showed unexpected interstitial changes in the lower lobes of both lungs, suggesting an NSIP pattern. Histopathology of the lung tissue in this region confirmed well-formed noncaseating epithelioid granulomas and pathological modifications of NSIP. After a rigorous exclusion diagnosis combining the patient's clinical features, radiological and pathological findings, we diagnosed this patient with pulmonary sarcoidosis comorbid with NSIP.

Conclusions: This suggests that NSIP may act as a rare comorbidity of pulmonary sarcoidosis thereby resulting in the patient's HRCT presenting differently from routine sarcoidosis imaging.