1 Introduction
With routine prenatal ultrasound scans performed, more and more
congenital cystic lesions of the lung are diagnosed in infants[1],
but the incidence is rare, which is present in 1 per 10,000–35,000
births[2]. The differential diagnosis of congenital cystic lesions
contains congenital cystic adenomatoid malformation (CCAM), pulmonary
sequestration (PS), bronchogenic cyst, congenital lobar emphysema (CLE),
and persistent pulmonary interstitial emphysema (PPIE) and so on.
Pulmonary interstitial emphysema (PIE) is a rare cystic disease of
infants. PIE is an air leak syndrome, characterized by gas dissecting
pulmonary interstitium, along the bronchovascular bundles. There are
three clinical types of PIE, including acute IPE, local persistent PIE
(LPPIE) and diffuse persistent PIE (DPPIE) [3, 4]. Acute IPE is
lesser than seven days in duration, diffuse persistent PIE is observed
when small cysts are noted in all lobes of the lung, while local
persistent PIE affected only one lobe [5]. Chest computed tomography
(CT) scan sometimes was limited to diagnose PIE. Sometimes, CT showed
cystic lung lesions mimicking CCAM in the postnatal period[6]. The
definitive diagnosis is histological. A histological diagnosis of PIE
was established through the wall of cysts composed of a thin layer of
discontinuous fibrous tissue and lined with uninucleated or/and
multinucleated macrophages[7, 8].
PIE frequently occurs in premature infants with positive pressure
mechanical ventilation[9, 10]. However, it has also been reported
rarely in both nonventilated infants and full-term infants[11, 12].
Pursnani et al.[12] showed a 3-month-old infant with LPPIE who had
no history of respiratory distress syndrome (RDS) and mechanical
ventilation, the patient had a medical history of viral pneumonia 1
month prior to surgery, indicating respiratory infection may be
associated with PPIE.
However, there were just a few reports of PPIE with respiratory
infection[11-19], and possible infectious pathogens were still
unclear. With the development of molecular methods of identification,
the metagenomic next-generation sequencing (mNGS) is a novel, rapid,
simple, and convenient approach in the clinical identification of
infectious diseases.
In present study, we reported six rare cases of PPIE with respiratory
infection, followed by successfully surgical lobectomy. To our best
knowledge, it is the first time to detect the possible infectious
pathogens in PPIE by using mNGS.