Secondary pulmonary alveolar proteinosis: a single-center retrospective study (a case series and literature review)

Dongmei Zhang,Ruie Feng,Kai-Feng Xu,Yusen Situ,Xiaobei Guo,Xinlun Tian,Peng Wang,Yi Xiao

doi:10.1186/s12890-018-0590-z

Abstract

BackgroundSecondary pulmonary alveolar proteinosis (sPAP) is an extremely rare disease. The clinical features of sPAP patients remain to be summarizeds. MethodsPatients pathologically diagnosed with PAP and with negative results for anti-granulocyte macrophage colony stimulating factor (GM-CSF) autoantibodies from Peking Union Medical College Hospital between January 2000 and July 2016 were retrospectively studied. The PubMed database was also searched for literature to collect published cases.ResultsIn our center, nine patients were diagnosed as sPAP with a median age of 37 years. Hematological disorders, including myelodysplastic syndrome (MDS), chronic myelogenous leukemia (CML), and pulmonary tuberculosis (TB) infection were the underlying diseases. Cases secondary to MDS had very poor prognosis as all of them survived less than 2 years after their diagnosis, while those secondary to TB had favorable prognosis. Only 33.3% of cases showed interlobular septal thickening in our sPAP group. Through literature review, 164 sPAP cases were collected. The age at diagnosis was 45.0 ± 14.8 years old and the gender radio was 1.20:1 (M:F). 61.9% of cases were diagnosed by bronchoscopy. MDS and CML were common underlying diseases in 34.1% and 15.2% of patients, respectively. Patients with sPAP secondary to hematological diseases had a short survival time and half of them died within 14.95 months after diagnosis.ConclusionsMDS and TB infection were the most frequent underlying causes of sPAP in this single-center research in China, with cases secondary to MDS having a poor survival rate. sPAP was more likely to be secondary to hematological disorders, especially MDS and CML and had a fairly poor prognosis in published cases. sPAP should be suspected in PAP patients whose CT scan presents only ground-glass opacities without interlobular septal thickening.

Highlights

Secondary pulmonary alveolar proteinosis is an extremely rare disease
As we do not know whether the prevalence of Secondary pulmonary alveolar proteinosis (sPAP) in China has any differences compared to other countries, we retrospectively collected sPAP patients hospitalized from 2000 to 2016 in our hospital, listed their clinical features and symptoms, and we reviewed all published cases in literature to learn more about the characteristics of sPAP around the world
Primary diseases The primary diseases of these 9 sPAP cases were variable, as 5 cases arose from hematologic disorders (4 myelodysplastic syndrome (MDS) and 1 chronic myelogenous leukemia (CML)) and 4 cases from tuberculosis (TB)

Summary

Introduction

Secondary pulmonary alveolar proteinosis (sPAP) is an extremely rare disease. The clinical features of sPAP patients remain to be summarizeds. Pulmonary alveolar proteinosis (PAP), a rare disease with an estimated prevalence of 3.7 to 6.2 cases per million persons [1, 2], is characterized by the accumulation of lipoprotein material in alveoli and terminal respiratory airways [3]. Knowledge of the clinical characteristics of sPAP are still limited as the majority of current literature is in the form of case reports, the largest series being a report by Ishii H which included 40 Japanese patients [7]. As we do not know whether the prevalence of sPAP in China has any differences compared to other countries, we retrospectively collected sPAP patients hospitalized from 2000 to 2016 in our hospital, listed their clinical features and symptoms, and we reviewed all published cases in literature to learn more about the characteristics of sPAP around the world

Methods

Results

Discussion

Conclusion