Usual Interstitial Pneumonia with Granuloma. Idiopathic Pulmonary Fibrosis Versus Chronic Hypersensitivity Pneumonitis
Kyoko Otani, Tomonori Tanaka, Junya Fukuoka. Toyama University Hospital, Toyama, Japan
Background: When granulomas are found in usual interstitial pneumonia (UIP), chronic hypersensitivity pneumonitis (CHP) is always in the differential diagnosis, but presence of a few granulomas can be just an incidental finding of idiopathic pulmonary fibrosis (IPF). Clear distinction between IPF and CHP is challenging for sometimes. Here, we compared the clinico-pathological features of UIP with granuloma and those with IPF to see if there are any other differences.
Design: A total of sixteen UIP with granuloma (UIP-G) patients and fifteen IPF patients were collected. Clinical, radiological, and histopathological findings in both groups were observed and compared. Prognosis was evaluated by the pulmonary function tests. The statistical analyses were performed using Mann-Whitney's U-test and Fisher's exact test. P values <.05 were considered statistically significant.
Results: Mean age of UIP-G and IPF was 61.2 and 64.5 years, respectively. Both showed male predominance (81% and 73%), and smoking experience was also similar (75% and 80%). Exposure history was positive for twelve in UIP-G and eight in IPF. In computed tomography, IPF showed honeycombing and lung volume loss more frequently than UIP-G (p<.01 in both). Lower and peripheral distribution was most frequent in both groups, though upper lung predominance was seen in two of UIP-G and one of IPF cases. Histopathologically, inflammatory cell infiltration was more frequent in UIP-G (p=.024) whereas honeycombing and vascular wall thickness were significantly severe in IPF (p<.01 and p=.019). There was no significant difference regarding fibroblastic foci, small airway disease, and airway centered change. IPF showed significantly worse outcomes of the forced vital capacity and the diffusing capacity of carbon monoxide than UIP-G (p=.045). Nine cases of UIP-G were suspected as CHP by clinical-radiological-pathological discussion, while six cases were considered as IPF.
Conclusions: Although patient demographics are similar, UIP with granuloma showed several different pathological and radiological features and clinical course from IPF. It is still unclear whether UIP with granuloma is a homogenous condition, but our data indicates that it seems to be distinct from IPF and that granuloma in UIP may not be just an incidental finding of IPF but suggest a different inflammatory process associated with better prognosis, probably of CHP.
Monday, March 19, 2012 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 295, Monday Morning