Cryptogenic Organizing Pneumonia

Abstract

Organizing pneumonia (OP) is a pathological pattern defined by the characteristic presence of buds of granulation tissue within the lumen of distal pulmonary airspaces consisting of fibroblasts and myofibroblasts intermixed with loose connective matrix. This pattern is the hallmark of a clinical pathological entity, namely cryptogenic organizing pneumonia (COP) when no cause or etiologic context is found. The process of intraalveolar organization results from a sequence of alveolar injury, alveolar deposition of fibrin, and colonization of fibrin with proliferating fibroblasts. A tremendous challenge for research is represented by the analysis of features that differentiate the reversible process of OP from that of fibroblastic foci driving irreversible fibrosis in usual interstitial pneumonia because they may determine the different outcomes of COP and idiopathic pulmonary fibrosis (IPF), respectively. Three main imaging patterns of COP have been described: (1) multiple patchy alveolar opacities (typical pattern), (2) solitary focal nodule or mass (focal pattern), and (3) diffuse infiltrative opacities, although several other uncommon patterns have been reported, especially the reversed halo sign (atoll sign). Definitive diagnosis is based on (1) a suggestive clinical radiological presentation, (2) the demonstration of the characteristic pathological pattern at lung histopathology, and (3) exclusion of possible causes. Transbronchial biopsies or a transthoracic biopsy may also contribute to the pathological diagnosis. Rapid clinical and imaging improvement is obtained with corticosteroid therapy. Because of the risk of misdiagnosing alternative conditions that may mimic OP, only typical cases may be managed without histopathological confirmation, and patients should be followed with particular attention paid to any clue of alternate diagnosis, especially in case of incomplete response to treatment. Patients and clinicians must be aware of frequent relapses after stopping corticosteroid treatment.

Cryptogenic organizing pneumonia: clinical and radiological features, treatment outcomes of 17 patients, and review of the literature

“…In the present study, the mean age of our patients was 49.8 years and 10 of them were female. The number of female patients was slightly higher in the present study, and this was similar to the study of Lazor et al (10). COP is, in particular, more prevalent in nonsmoking females and/or females who have stopped smoking (10).…”

“…The number of female patients was slightly higher in the present study, and this was similar to the study of Lazor et al (10). COP is, in particular, more prevalent in nonsmoking females and/or females who have stopped smoking (10). In our patient group, 11 of the 17 patients were nonsmokers, and two of the three female smokers had stopped smoking.…”

“…Contrary to the present study, Oymak et al diagnosed by TBB in 46% of their cases (3). Lazor et al diagnosed COP by OLB/VATS in 69% of 48 cases and by TBB in 31% (10). Although the number of patients was different than ours, the rate of diagnostic methods used was similar to that used in our study.…”

“…Migratory bilateral patchy alveolar infiltrates are the most typical imaging patterns of COP (2,8,13). Alveolar opacities were reported with a prevalence of 69% to 82% (10,12,16). Drakopanagiotakis et al determined consolidation in 82% of their cases and observed migrating infiltrates in 11.5% of them (12).…”

Elective preterm delivery as a management option in cryptogenic organizing pneumonia

“…1,2 The original terminology of bronchiolitis obliterans organizing pneumonia has been abandoned because the major process is organizing pneumonia with bronchiolitis obliterans being only a minor and accessory finding that may even be absent. 3 COP remains a rare disease in pregnancy with only two prior cases reported in the literature. To our knowledge, we report the first case of pre-existing COP in pregnancy.…”