Smoking-Related Interstitial Fibrosis (SRIF) in Patients Presenting With Diffuse Parenchymal Lung Disease

Abstract

Objectives To describe the clinical, radiologic, and pathologic findings in cases where smoking-related interstitial fibrosis (SRIF) was diagnosed in surgical lung biopsy specimens from patients with clinical and imaging features of diffuse parenchymal lung disease (DPLD). Methods Cases were included in this study if patients had clinical and imaging evidence of DPLD and surgical lung biopsy specimens revealed SRIF. A dedicated multidisciplinary conference was held to correlate clinical, radiologic, and pathologic findings. Results Six cases met inclusion criteria; all six (five women/one man, aged 42-57 years, mean age 47 years) were either current smokers (five of six) or ex-smokers (one of six) and were evaluated for respiratory symptoms and abnormal pulmonary function tests, most commonly reduced forced vital capacity (n = 3) and diffusing capacity for carbon monoxide (n = 6). The most common imaging abnormalities were bilateral ground-glass opacities, which correlated with histopathologic SRIF. Follow-up of up to 10 years showed stable or improved clinical symptoms, pulmonary function tests, and radiologic findings with smoking cessation (three patients) or a decrease in smoking (three patients). No specific treatments were given, and those treated with empiric corticosteroid tapers did not show discernible responses. Conclusions SRIF can present as clinically meaningful diffuse parenchymal lung disease in relatively young heavy smokers, characterized by bilateral ground-glass opacities and a stable clinical course.

Smoking-Related Interstitial Fibrosis and Smoker's Macrophages

“…High-resolution computed tomography (HRCT) plays a prominent role in diagnosis. Vehar et al reported their review of imaging and surgical lung biopsy findings in SRIF 19 . Bilateral ground-glass opacities (GGOs) were the dominant feature in all cases and correlated with the presence of SRIF and pigmented airspace macrophages on histopathological examination.…”

“…According to six cases of SRIF reported by Vehar et al 19 , using the Global Initiative for Chronic Obstructive Lung Disease criteria 23 , two patients had obstruction on PFTs, defined by an FEV1/forced vital capacity (FVC) ratio of 0.7. All patients had a predicted FEV1% of 70%, with a median value of 72% and a range of 70-92%.…”

“…Reports on the prognosis and longitudinal follow-up of patients with SRIF are sparse. Several reports suggest that although symptoms such as dyspnea and cough may persist, SRIF does not progress significantly over nearly 10 years of clinical follow-up and may show slight improvements in pulmonary function and long-term stability of radiologic findings with smoking cessation or reduction 12,15,19,24 . Accordingly, in cases of clinical or imaging features of progressive pulmonary fibrosis, the so-called progressive fibrosing interstitial lung disease (PF-ILD), the diagnosis itself should be re-evaluated, and indications for anti-fibrotic therapy…”