[1922] Focal Pulmonary Alveolar Proteinosis Is a Common Reaction and Progression Indicator in Idiopathic Pulmonary Fibrosis

Sayuri Nunomura, Tomonori Tanaka, Kyoko Otani, Kazuhiro Tabata, Yasuhiro Kondoh, Kensuke Kataoka, Takeshi Johkoh, Hiroyuki Taniguchi, Junya Fukuoka. Toyama University Hospital, Toyama, Japan; Tosei General Hospital, Seto, Japan; Kinki Central Hospital, Itami, Japan

Background: We have experienced cases of chronic interstitial pneumonia (IP) showing focal histologic features simulating pulmonary alveolar proteinosis (PAP). The occurrence and the meaning of focal PAP (fPAP) in the cases of chronic IP are unclear.
Design: 146 cases with chronic IP were selected from the consultation archive of Toyama University Hospital. Clinical records and histological specimens were reviewed. Immunohistochemical staining for fPAP; against surfactant protein-A (SP-A) was performed for unstained slides. Idiopathic pulmonary fibrosis (IPF) cases with fPAP were extracted and compared to the IPF cases without fPAP. Histological findings such as honeycomb cyst (HC), fibroblastic focus, and small airway disease were observed, and cases were separated to positive or negative based on the severity in each finding. Several statistical tests were performed depending on the distribution of the data.
Results: Twenty of 146 cases (13.7%) were identified to have fPAP [Figure A, B]. Focal PAP was strongly positive to SP-A [Figure C]. Among those 20 cases, 15 cases were IPF, and the incidence of fPAP in IPF patients was 15/56 (26.8%). In the comparison between IPF with and without fPAP, HC was solely associated with fPAP among histological findings (P = 0.016) [Table 1]. Furthermore, lower %FVC and higher serum KL-6 were associated with fPAP (P = 0.022, 0.005, respectively).

Histological findings of idiopathic pulmonary fibrosis with and without focal pulmonary alveolar proteinosis
 fPAP (n=15)No fPAP (n=21)P value
Honeycomb cyst13 (87%)10 (47%)0.016
Fibroblastic foci12 (80%)14 (67%)0.468
Small airway disease7 (47%)15 (71%)0.133
Cellular interstitial pneumonia6 (40%)5 (24%)0.465
Dust deposition4 (27%)7 (33%)0.729
Lymphoid follicle5 (33%)5 (24%)0.709
fPAP, focal pulmonary alveolar proteinosis;

Conclusions: We found that the IPF frequently show fPAP. Focal PAP in IPF associated with decline of %FVC, severity of HC, and serum KL-6, all of which indicates that presence of fPAP may be a histopathological indicator of disease progression.
Category: Pulmonary

Tuesday, March 5, 2013 1:00 PM

Poster Session IV # 284, Tuesday Afternoon


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