{Reference Type}: Journal Article {Title}: Organizing pneumonia components in non-specific interstitial pneumonia (NSIP): a clinicopathological study of 33 NSIP cases. {Author}: Huo Z;Li J;Li S;Zhang H;Jin Z;Pang J;Liu H;Shi J;Feng R; {Journal}: Histopathology {Volume}: 68 {Issue}: 3 {Year}: Feb 2016 {Factor}: 7.778 {DOI}: 10.1111/his.12761 {Abstract}: OBJECTIVE: To review the clinical, radiological and pathological features of non-specific interstitial pneumonia (NSIP), mainly to characterize organizing pneumonia (OP) components in NSIP.
RESULTS: Lung biopsy samples from 33 NSIP patients were collected over a period of 10 years. Microscopic analysis revealed that 13 cases showed a cellular pattern and 20 showed a mixed/fibrosing pattern. OP components were detected in 26 cases (13 with a cellular pattern; 13 with a mixed/fibrosing pattern), and were found to constitute a median proportion of 9% (range, 1-40%) of the affected tissues. In nine cellular and four mixed/fibrosing NSIP cases, the OP components accounted for ≥10%. A proportion of ≥20% was found in only five cellular pattern cases. Twenty-nine patients were followed up: 17 showed improvements, five were stabilized, and seven showed progression.
CONCLUSIONS: OP components are common basic lesions in NSIP cases, although their proportion in cellular and mixed/fibrosing pattern cases varies substantially between patients. OP components do not impact on prognosis, even when they constitute ≥20% of the affected tissue. Thus, a high level of OP components does not exclude a diagnosis of NSIP in cases that otherwise show pathological and radiological findings characteristic of NSIP.