[Clinicopathologic study of 50 autopsy cases of idiopathic pulmonary fibrosis and non-diffuse usual interstitial pneumonia].

We investigated 50 autopsy cases of idiopathic pulmonary fibrosis (IPF) and non-diffuse usual interstitial pneumonia (UIP), and subgrouped them into three subtypes based on morphologic differences in the fibrosis (honeycomb): typical thick-walled honeycomb type (16 cases), atypical thin-walled honeycomb type (27 cases) and atelectatic indurated type (6 cases), with one undetermined case. In the thin-walled type, the percentage of males (93%), the percentage of smokers (89%), and the percentage of lung cancer cases (52%) were significantly higher than in the other two subtypes (p < 0.02, p < 0.001 and p < 0.05, respectively). However, in the thick-walled and indurated types there were significantly higher percentages of DAD (38% and 67%, respectively) than in the thin-walled type (15%) (P < 0.05). Accordingly, each subtype was thought to be closely related to its IPF clinical features, and showed differences in the development of acute exacerbation and lung cancer. This study proposes the existence of a UIP subset and suggests that this subgrouping can help in the management of the disease.