Organizing pneumonia/non-specific interstitial pneumonia overlap is associated with unfavorable lung disease progression

Abstract

OP/NSIP overlap, either idiopathic or autoimmune-associated and identified by histologic and radiologic findings, was associated with unfavorable disease progression, and should therefore be recognized as a characteristic clinical-radiologic-histologic entity.

Expanded acceptance of acute exacerbation of nonspecific interstitial pneumonia, including 7 additional cases with detailed clinical pathologic correlation

“…4,20 The presence of OP lesion in the setting of NSIP has been recognized as a manifestation of subacute lung injury 21 and reported to be associated with autoimmune diseases with subsequent disease progression. 22,23 Alveolar hemorrhage was seen only in patients with acute exacerbation of NSIP in the present study. However, it is important to note that alveolar hemorrhage is not specific for lung injury per se, as it can also be seen as a sequela of heart failure, the latter of which can similarly cause respiratory distress.…”

“…OP lesion is a nonspecific pathologic feature that is found mainly in acute or subacute disease processes . The presence of OP lesion in the setting of NSIP has been recognized as a manifestation of subacute lung injury and reported to be associated with autoimmune diseases with subsequent disease progression …”

“…For these patients, we cannot exclude the possibility that the prominent OP lesions in the biopsy represent an acute/subacute process that subsequently evolved into a fibrosing lesion. Such lesions, variably described in the literature as "NSIP/OP overlap" 23 or "fibrosing variants of OP" 25 may make it difficult to use OP lesions as the sole criterion for predicting acute exacerbation in the setting of NSIP. 26 This study included patients with both clinically "suspected" as well as "definite" acute exacerbation, as defined by the ATS.…”

Serial chest CT in cryptogenic organizing pneumonia: Evolutional changes and prognostic determinants

“…It is known that histopathologically separating COP from NSIP is potentially difficult . Furthermore, according to a histopathological report, histologic COP coexisted with fNSIP in 21 of 31 (68%) patients. Similarly, it is also hard to distinguish between treated and residual COP and fNSIP with CT findings.…”

“…However, despite this therapy, cases of relapse or progression have been reported . Most patients (73%, 16 of 22 patients) with COP have some residual disease on follow‐up CT and in such cases the lung lesions generally resemble a fibrotic non‐specific interstitial pneumonia (fNSIP) pattern. Moreover, the histopathology of COP is reported as fibrinous exudate in acute fibrinous organizing pneumonia, with fNSIP in fibrosing variant of organizing pneumonia or COP/fNSIP overlap and peribronchiolar granuloma in hypersensitivity pneumonia .…”