An autopsy study of combined pulmonary fibrosis and emphysema: correlations among clinical, radiological, and pathological features

Abstract

Background: Clinical evaluation to differentiate the characteristic features of pulmonary fibrosis and emphysema is often difficult in patients with combined pulmonary fibrosis and emphysema (CPFE), but diagnosis of pulmonary fibrosis is important for evaluating treatment options and the risk of acute exacerbation of interstitial pneumonia of such patients. As far as we know, it is the first report describing a correlation among clinical, radiological, and whole-lung pathological features in an autopsy cases of CPFE patients.

Methods: Experts retrospectively reviewed the clinical charts and examined chest computed tomography (CT) images and pathological findings of an autopsy series of 22 CPFE patients, and compared these with findings from 8 idiopathic pulmonary fibrosis (IPF) patients and 17 emphysema-alone patients.

Results: All patients had a history of heavy smoking. Forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC%) was significantly lower in the emphysema-alone group than the CPFE and IPF-alone groups. The percent predicted diffusing capacity of the lung for carbon monoxide (DLCO%) was significantly lower in the CPFE group than the IPF- and emphysema-alone groups. Usual interstitial pneumonia (UIP) pattern was observed radiologically in 15 (68.2%) CPFE and 8 (100%) IPF-alone patients and was pathologically observed in all patients from both groups. Pathologically thick-cystic lesions involving one or more acini with dense wall fibrosis and occasional fibroblastic foci surrounded by honeycombing and normal alveoli were confirmed by post-mortem observation as thick-walled cystic lesions (TWCLs). Emphysematous destruction and enlargement of membranous and respiratory bronchioles with fibrosis were observed in the TWCLs. The cystic lesions were always larger than the cysts of honeycombing. The prevalence of both radiological and pathological TWCLs was 72.7% among CPFE patients, but no such lesions were observed in patients with IPF or emphysema alone (p=0.001). The extent of emphysema in CPFE patients with TWCLs was greater than that in patients without such lesions. Honeycombing with emphysema was also observed in 11 CPFE patients.

Conclusions: TWCLs were only observed in the CPFE patients. They were classified as lesions with coexistent fibrosing interstitial pneumonia and emphysema, and should be considered an important pathological and radiological feature of CPFE.

Figure 1

Representative computed tomography (CT) scans performed within 1 month of death in a patient with combined pulmonary fibrosis and emphysema (CPFE) without lung cancer who died from pulmonary hypertension (A, B), and in another such patient with lung cancer who died from a non-respiratory cause (C). (A) Upper lobe showing centrilobular and paraseptal emphysema and bullae. (B) Lower lobe showing reticular opacities with peripheral and basal predominance and honeycombing, which was diagnosed as definite usual interstitial pneumonia (UIP) pattern. (C) Lower lobe showing thick-walled cystic lesions (TWCLs) larger than honeycombing with peripheral reticular opacities.

Figure 2

Gross photo showing marked upper lobe emphysema with fibrosis and lower lobe fibrosis and honeycomb lesion with emphysematous change in the lungs of a CPFE patient without lung cancer.

Figure 3

Images of a CPFE patient with lung cancer in the right lower lobe who died from a non-respiratory cause. (A) CT scan performed within 1 month of death; view of the left lower lobe showing TWCLs with slight reticulation on the pleural predominance. (B) Paramount view showing pathological TWCLs with fibrosis in the left lower lobe; corresponds to the CT scan (Figure 3-A). TWCLs involving the bronchiole and parenchyma with a dense fibrous wall beneath the terminal bronchioles. (C) High-power view of the square lesion in Figure 3-B showing fibroblastic focus in the fibrous walls.

Figure 4

Images of a CPFE patient without lung cancer who died from right heart failure owing to deterioration of pulmonary hypertension. (A) CT scan performed 6 months prior to death; view of the right lower lobe showing TWCLs and traction bronchiectasis with reticulation on the pleural predominance. (B) CT scan performed within 1 month of death showing enlargement of TWCLs and simultaneous progression of reticulation despite smoking cessation. (C) Gross photo of the right lower lobe showing TWCLs (square). (D) Paramount view showing TWCLs apposed to honeycombing in the right lower lobe; corresponds to the CT scan (Figure 4-B) and gross photo (Figure 4-C). (E) High-power view of the square lesion in Figure 4-D showing fibroblastic focus (arrow) in the fibrous walls of the TWCLs.

Figure 5

Images of a CPFE patient with lung cancer who died from a pulmonary infarction. (A) CT scan performed within 1 month of death showing honeycombing with a thin wall and the occasional integration of cysts in the left lower lobe. (B) Image of the lower lobe showing enlarged honeycomb cysts with thin walls and remnant of lung tissue therein corresponding to the CT scan (Figure 5-A). (C) High-power view of the square lesion in Figure 5-B showing perilobular atelectatic fibrosis with smooth muscle hyperplasia.