Clinical, radiological, and pathological evaluation of "NSIP with OP overlap" pattern compared with NSIP in patients with idiopathic interstitial pneumonias

Noriyuki Enomoto; Hiromitsu Sumikawa; Hiroaki Sugiura; Masashi Kitani; Tomonori Tanaka; Hironao Hozumi; Tomoyuki Fujisawa; Takafumi Suda

doi:10.1016/j.rmed.2020.106201

Clinical, radiological, and pathological evaluation of "NSIP with OP overlap" pattern compared with NSIP in patients with idiopathic interstitial pneumonias

Respir Med. 2020 Nov-Dec:174:106201. doi: 10.1016/j.rmed.2020.106201. Epub 2020 Oct 21.

Authors

Noriyuki Enomoto¹, Hiromitsu Sumikawa², Hiroaki Sugiura³, Masashi Kitani⁴, Tomonori Tanaka⁵, Hironao Hozumi⁶, Tomoyuki Fujisawa⁶, Takafumi Suda⁶

Affiliations

¹ Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan; Health Administration Center, Hamamatsu University School of Medicine, Hamamatsu, Japan. Electronic address: norieno@hama-med.ac.jp.
² Department of Diagnostic Radiology, Sakai City Medical Centre, Osaka, Japan.
³ Department of Radiology, National Defense Medical College, Saitama, Japan.
⁴ Department of Pathology, National Hospital Organization Tokyo National Hospital, Tokyo, Japan.
⁵ Department of Diagnostic Pathology, Kobe University Hospital, Hyogo, Japan.
⁶ Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan.

PMID: 33120192
DOI: 10.1016/j.rmed.2020.106201

Abstract

Background: Nonspecific interstitial pneumonia (NSIP) and organizing pneumonia (OP) are major subtypes of idiopathic interstitial pneumonias (IIPs) and closely related to connective tissue diseases (CTDs). "NSIP with OP overlap" is a controversial finding that has recently appeared in the criteria of interstitial pneumonia with autoimmune features (IPAF). However, details of this controversial entity are not well known.

Objective: To determine the frequency of "NSIP with OP overlap" pattern in IIPs and to identify differences from idiopathic NSIP (iNSIP).

Methods: In 524 patients with interstitial pneumonia from 39 institutes who underwent surgical lung biopsy, 444 were diagnosed as IIPs by a multidisciplinary discussion meeting via a cloud-based integrated database. Among these patients, 44 (9.9%) who had iNSIP and 21 (4.7%) with histopathologically-defined "NSIP with OP overlap" pattern (a pathological NSIP and OP pattern, but without a UIP pattern) were retrospectively studied.

Results: Patients with "NSIP with OP overlap" pattern showed a significantly greater extent of consolidation (p < 0.001), more subpleural ground glass attenuation (p = 0.036), and more peripheral + bronchovascular distribution (p = 0.009) on high-resolution computed tomography than those with iNSIP. The incidences of newly-developed CTDs during follow-up was similar between the groups and polymyositis/dermatomyositis was the most frequent CTD in both groups. Nearly half of the patients fulfilled IPAF criteria, but no significant difference was found between iNSIP and "NSIP with OP overlap" pattern (47.7% vs. 42.9, p = 0.712). The incidence of acute exacerbation and the survival rates were similar between the groups.

Conclusions: The incidence of "NSIP with OP overlap" pattern is 4.7% in IIPs. The frequency of newly-developed CTDs during follow-up, mainly polymyositis/dermatomyositis, the frequency of acute exacerbation, and the survival rate in "NSIP with OP overlap" pattern are similar to those of iNSIP.

Keywords: Idiopathic interstitial pneumonia; Interstitial pneumonia with autoimmune features; Nonspecific interstitial pneumonia; Organizing pneumonia; Unclassifiable interstitial pneumonia.

MeSH terms

Adult
Aged
Aged, 80 and over
Dermatomyositis
Diagnosis, Differential
Female
Follow-Up Studies
Humans
Idiopathic Interstitial Pneumonias / diagnostic imaging*
Idiopathic Interstitial Pneumonias / pathology*
Lung / diagnostic imaging*
Lung / pathology*
Male
Middle Aged
Polymyositis
Retrospective Studies
Tomography, X-Ray Computed