Radiologic-Pathologic CorrelationUsual interstitial pneumonia end-stage features from explants with radiologic and pathological correlations☆
Introduction
Idiopathic pulmonary fibrosis (IPF) is the most frequent and the most severe idiopathic interstitial pneumonia. It is a chronic and progressive fibrotic disease limited to the lung, which predominates in males and smokers. Idiopathic pulmonary fibrosis is a clinicopathologic entity with a dismal prognosis and no response to anti-inflammatory therapy. According to the 2011 ATS/ERS/JRS/ALAT guidelines, the diagnosis of IPF is based on high-resolution computed tomography (HRCT) findings, including reticulations and honeycombing predominating in subpleural regions, with or without traction bronchiectases, a histologic pattern of usual interstitial pneumonia (UIP), and the exclusion of known causes of interstitial pneumonias, especially environmental exposure, medication, or systemic disease [1]. The histologic pattern of UIP is defined by dense fibrosis responsible for architectural distortion, subpleural and paraseptal honeycombing, patchy involvement of the lung with areas of normal lung, fibroblastic foci, and none of the following criteria, that is, hyaline membranes, organizing pneumonia (except in the setting of an acute exacerbation [AE] of the disease), marked inflammation, predominant airways changes, and other features suggesting an alternative diagnosis. However, because of interobserver discrepancies between pathologists reported in several studies and the possibility of sampling issues, histopathology is no longer the criterion standard for the diagnosis of IPF [2], [3], [4], [5], [6]. Pathologists are asked to describe the pattern of interstitial lung disease rather than to make definite diagnosis, patterns being further discussed along with clinicoradiologic findings and included in a final consensus diagnosis [1].
The main clinical and histologic differential diagnosis of UIP/IPF is represented by nonspecific interstitial pneumonia (NSIP) [7], which is associated with a better prognosis and response to corticosteroids [8], [9]. In contrast to UIP, the NSIP pattern is characterized histologically by uniform distribution of interstitial inflammation and fibrosis lacking the patchwork involvement of UIP. However, the NSIP fibrotic pattern may be difficult to distinguish from the UIP pattern.
As most histologic criteria for interstitial lung diseases have been described from open lung biopsies (OLBs), the present study was conducted to describe the end-stage histologic features of UIP on explants, to compare them with previous OLB when available, and to make a correlation between radiology, OLB, and explants.
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Materials and methods
Twenty-two patients transplanted for pulmonary fibrosis were identified from the University Hospital of Grenoble files between 1991 and 2009 and from the University Hospital Lyon-Est files between 2000 and 2009.
Lung explants' specimens were available for analysis in all cases. In addition, OLBs performed prior to the lung transplantation were available for review in 11 cases (50%). All biopsies and explants were retrospectively analyzed by 4 pathologists (M.R., S.L., F.T., L.C.) blinded to the
Clinical data
Fourteen patients (64%) were smokers, and 20 were men and 2 were women; the mean age at the time of lung transplantation was 55 years. One patient had been formerly treated for tuberculosis, and for 3 patients, lung cancer (1 squamous cell carcinoma and 2 adenocarcinomas) was incidentally found on explants (Table 2).
The mean data of pulmonary function before transplantation were as follows: forced vital capacity 43.1% ± 12.0% of predicted; forced expiratory volume in 1 second, 44.9% ± 12.2%
Discussion
ATS/ERS/JRS/ALAT have recently published guidelines for the diagnosis and treatment of IPF [1], acknowledging the determinant role of CT scan for the diagnosis of IPF; OLBs are now only performed in a minority of the cases, around 30% [11], [12], mainly because surgical lung biopsies are potentially responsible for complications [13], [14], [15]. Because only 16% of IPF patients benefit from lung transplantation [11], clinical and radiologic features as well as OLB are rarely compared with
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2021, Human PathologyCitation Excerpt :In addition, interobserver variation is substantial in the detection of inflammatory cells [14,15]. Besides interstitial inflammation, intra-alveolar macrophages have been detected in IPF samples [9,16], but very little is known of their clinical or biological significance. Quantitating inflammatory cells manually from lung tissue samples is time consuming, inaccurate, and subject to intraobserver and interobserver variation, providing an explanation for the scant histological studies on inflammation in IPF.
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Conflicts of interest and source of funding: the authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this study.