Pulmonary cysts in early childhood and the risk of malignancy

Congenital Lung Malformations: A Pictorial Review of Imaging Findings and a Practical Guide for Diagnosis

The term congenital lung malformation (CLM) is used to describe a wide range of pathological conditions with different imaging and clinical manifestations. These anomalies stem from abnormal embryological lung development, potentially occurring across various stages of prenatal life. Their natural history can be variable, presenting in a wide range of severity levels and encompassing asymptomatic individuals who remain so until adulthood, as well as those who experience respiratory distress in the neonatal period. Through the PubMed database, we performed an extensive review of the literature in the fields of congenital lung abnormalities, including their diagnostic approach and findings. From our RIS-PACS database, we have selected cases with a final diagnosis of congenital lung malformation. Different diagnostic approaches have been selected, including clinical cases studied using plain radiograph, CT scan, prenatal ultrasound, and MR images. The most encountered anomalies can be classified into three categories: bronchopulmonary anomalies (congenital pulmonary airway malformations (CPAMs), congenital lobar hyperinflation, bronchial atresia, and bronchogenic cysts), vascular anomalies (arteriovenous malformation), and combined lung and vascular anomalies (scimitar syndrome and bronchopulmonary sequestration). CLM causes significant morbidity and mortality; therefore, the recognition of these abnormalities is necessary for optimal prenatal counseling and early peri- and postnatal management. This pictorial review aims to report relevant imaging findings in order to offer some clues for differential diagnosis both for radiologists and pediatric consultants.

A genome-first approach to characterize DICER1 pathogenic variant prevalence, penetrance and cancer, thyroid, and other phenotypes in 2 population-scale cohorts

Purpose

Population-scale, exome-sequenced cohorts with linked electronic health records (EHR) permit genome-first exploration of phenotype. Phenotype and cancer risk are well-characterized in children with a pathogenic DICER1 (HGNC ID:17098) variant. Here, the prevalence, penetrance and phenotype of pathogenic germline DICER1 variants in adults was investigated in two population-scale cohorts.

Methods

Variant pathogenicity was classified using published DICER1 ClinGen criteria in the UK Biobank (469,787 exomes; unrelated: 437,663) and Geisinger (170,503 exomes; unrelated: 109,789) cohorts. In the UK Biobank cohort, cancer diagnoses in the EHR, cancer and death registry were queried. For the Geisinger cohort, the Geisinger Cancer Registry and EHR were queried.

Results

In the UK Biobank, there were 46 unique pathogenic DICER1 variants in 57 individuals (1:8,242;95%CI:1:6,362-1:10,677). In Geisinger, there were 16 unique pathogenic DICER1 variants (including one microdeletion) in 21 individuals (1:8,119;95%CI:1:5,310-1:12,412). Cohorts were well-powered to find larger effect sizes for common cancers. Cancers were not significantly enriched in DICER1 heterozygotes; however, there was a ~4-fold increased risk for thyroid disease in both cohorts. There were multiple ICD10 codes enriched >2-fold in both cohorts.

Conclusion

Estimates of pathogenic germline DICER1 prevalence, thyroid disease penetrance and cancer phenotype from genomically ascertained adults are determined in two large cohorts.

Perinatal Management of Pregnancies with Fetal Congenital Anomalies: A Guide to Obstetricians and Pediatricians

BACKGROUND

Congenital anomalies are responsible for approximately 20% of all neonatal deaths worldwide. Improvements in antenatal screening and diagnosis have significantly improved the prenatal detection of birth defects; however, these improvements have not translated into the improved neonatal prognosis of babies born with congenital anomalies.

OBJECTIVES

An attempt has been made to summarise the prenatal interventions, if available, the optimal route, mode and time of delivery and discuss the minimum delivery room preparations that should be made if expecting to deliver a fetus with a congenital anomaly.

METHODS

The recent literature related to the perinatal management of the fetus with prenatally detected common congenital anomalies was searched in English peer-reviewed journals from the PubMed database to work out an evidence-based approach for their management.

RESULTS

Fetuses with prenatally detected congenital anomalies should be delivered at a tertiary care centre with facilities for neonatal surgery and paediatric intensive care if needed. There is no indication for preterm delivery in the majority of cases. Only a few congenital malformations, like highrisk sacrococcygeal teratoma, congenital lung masses with significant fetal compromise, fetal cerebral lesions or neural tube defects with Head circumference >40 cm or the biparietal diameter is ≥12 cm, gastroschisis with extracorporeal liver, or giant omphaloceles in the fetus warrant caesarean section as the primary mode of delivery.

CONCLUSION

The prognosis of a fetus with congenital anomalies can be significantly improved if planning for delivery, including the place and time of delivery, is done optimally. A multidisciplinary team should be available for the fetus to optimize conditions right from when it is born.

Infantile type I pleuropulmonary blastoma presenting with dyspnea due to compression by pneumothorax and an occupying tumor: a case report

BACKGROUND

Pleuropulmonary blastoma (PPB) is an extremely rare and malignant pediatric lung tumor. Purely cystic PPB has a more favorable prognosis than solid PPB, but may be difficult to distinguish from a certain type of "benign" congenital pulmonary airway malformation before and during surgery. The influence of tumor rupture on long life prognosis has not been clarified in detail.

CASE PRESENTATION

A 5-month-old boy underwent emergency transfer from another hospital due to a left thoracic cystic lesion and left pneumothorax detected on chest radiography performed for persistent wheeze and cough. Contrast-enhanced computed tomography of the chest revealed marked deviation of the mediastinum to the right due to a giant cystic lesion and pneumothorax. Thoracotomy was performed on hospital day 2. A cystic lesion had developed from the distal alveolar region of lower lobe of the left lung and the tumor showed a tiny adhesion to the left diaphragm and a tiny rupture near the adhesion. Partial lung excision including the cyst and scraping of the adhesion were performed. Histopathological investigations revealed immature blast cell-like mesenchymal cells and differentiated striated muscle cells in a dense cambium layer were found under the epithelium of the cystic lesion. Type I PPB was diagnosed.

CONCLUSIONS

Surgery should be performed with the possibility of type I PPB in mind when an extrapulmonary cystic lung lesion is found. Since issues such as the pathogenesis and long-term prognosis of ruptured cases remain unclear, continued careful follow-up of this case will be required.

Congenital lung malformations

Congenital lung malformations (CLMs) are rare developmental anomalies of the lung, including congenital pulmonary airway malformations (CPAM), bronchopulmonary sequestration, congenital lobar overinflation, bronchogenic cyst and isolated congenital bronchial atresia. CLMs occur in 4 out of 10,000 live births. Postnatal presentation ranges from an asymptomatic infant to respiratory failure. CLMs are typically diagnosed with antenatal ultrasonography and confirmed by chest CT angiography in the first few months of life. Although surgical treatment is the gold standard for symptomatic CLMs, a consensus on asymptomatic cases has not been reached. Resection, either thoracoscopically or through thoracotomy, minimizes the risk of local morbidity, including recurrent infections and pneumothorax, and avoids the risk of malignancies that have been associated with CPAM, bronchopulmonary sequestration and bronchogenic cyst. However, some surgeons suggest expectant management as the incidence of adverse outcomes, including malignancy, remains unknown. In either case, a planned follow-up and a proper transition to adult care are needed. The biological mechanisms through which some CLMs may trigger malignant transformation are under investigation. KRAS has already been confirmed to be somatically mutated in CPAM and other genetic susceptibilities linked to tumour development have been explored. By summarizing current progress in CLM diagnosis, management and molecular understanding we hope to highlight open questions that require urgent attention.

Diagnostic accuracy of imaging compared to histology in congenital lung malformations

INTRODUCTION

The aim of this study was to evaluate the accuracy of imaging tests (prenatal ultrasound [US] and postnatal computed tomography [CT]) in comparison to histology for diagnosis of congenital lung malformations (CLMs).

MATERIAL AND METHODS

Retrospective study of patients with a prenatal diagnosis of CLM whose postnatal follow-up included thoracic CT scan and histological examination of the lesion. We collected data on demographic variables, gestational age at diagnosis, US findings and the history of multiple gestation. We used the kappa coefficient to determine the level of agreement between the findings of prenatal US and postnatal tests (CT and histology).We analysed paired data on the size of the lesion, its location and the presence or absence of systemic arterial vascularization.

RESULTS

The sample included 56 patients with 57 lesions. The mean gestational age at diagnosis was 22.42 weeks (SD, 3.94) and 57% were male. Malformations most frequently involved the left lung and the lower lobes. The agreement between CT and histology in the detection of cystic lesions was moderate (κ = 0.55) but stronger compared to the agreement between US and histology (κ = 0.10). The agreement between CT and histology was substantial (κ = 0.66) in the detection of systemic vascularization of the lesion and stronger compared to the agreement between US and histology. Both imaging methods were highly accurate in the identification of the location of the pulmonary lesions.

CONCLUSIONS

postnatal CT offers a substantial concordance with histological findings, especially in the detection of systemic vascularization, and an accurate prediction of the anatomy of the lesion.

A complete spectrum of congenital cystic adenomatoid malformation of the lung deceptive clinical presentations and histological surprises; a single institutional study from a tertiary care hospital in North India

Background

Congenital Cystic Adenomatoid Malformations (CCAM) are rare congenital anomalies of the lungs characterised by bronchopulmonary foregut malformations due to a sudden arrest in the development of the bronchial tree in the first trimester of the gestational period.

Aim

: The present study was aimed to describe the clinical and histopathological profiles of the patients and study patient outcomes after 1 year of surgical resection.

Methods

All patients diagnosed with CCAM by histological examination of tissue obtained on surgical resection during the study period were included in the study. Data, such as patient demographics and clinical, radiological and histopathological findings, were recorded, and follow-up information was taken on OPD follow-up till 1 year after surgery regarding respiratory infections, haemoptysis or mortality.

Results

: Out of 21 patients, 11 were female and included in the study between the ages of 1 month and 32 years, with >50% younger than 2 years. Most patients in the study had recurrent pneumonia, with difficulty in breathing being the second most common presenting complaint. All patients had undergone computed tomography (CT) of the lungs, which was able to diagnose cystic lesions accurately in >80% of cases. Histologically, all cases were classified based on recent Strocker's classification, and Type 1 was the most commonly observed with 13 cases, followed by Type 2 in five and Type 3 in three patients. There was no evidence of malignant transformation in any of the cases. There was 100% survival at the end of 1 year, with six patients having respiratory infections and none of the patients getting hospitalised over 1 year after surgery.

Conclusion

CCAM is a rare congenital anomaly associated with significant morbidity and may present at any age. It can be histologically classified into three subtypes, with Type 1 being the most common. Early surgical management is mandatory to prevent complications such as recurrent infections, respiratory distress, pneumothorax, lung abscess and malignant transformation. All patients included in the study had undergone surgical resection, and there was 100% survival at 1-year follow-up.

Uniportal video-assisted thoracoscopic anatomical resection of the right anterior pulmonary segment in a 10-year-old child with congenital pulmonary airway malformation

Congenital pulmonary airway malformation (CPAM) is a very rare phenomenon subject to malignant transformation that requires surgical resection. In an asymptomatic 10-year-old girl, we identified a single cystic and consolidated lesion on computed tomography. This incidental finding was confined to anterior segment of lung in right upper lobe (RUL). Uniportal video-assisted thoracoscopic surgery (VATS) served to successfully achieve anterior segmentectomy, without chest tube placement. The surgical specimen confirmed features of CPAM, also showing acute and chronic inflammation with abscess formation. Once the surgical mainstay for such lesions, open lobectomy is now under challenge by thoracoscopic technique, port-reduction methods, and a lung-preserving strategy. Herein, we have shown uniportal VATS anatomical resection of right anterior pulmonary segment to be a viable option for a 10-year-old child with CPAM confined to a single lung segment.

Intradiaphragmatic pulmonary sequestrations: a surgical challenge. Case series

Bronchopulmonary sequestrations (BPSs) are rare congenital anomalies characterized by non-functioning embryonic lung tissue receiving anomalous blood supply. They are most commonly located within the thorax (supradiaphragmatic) or into the abdominal cavity (infradiaphragmatic). Intradiaphragmatic extralobar BPs (IDEPS) are an exceptionally rare finding, representing a diagnostic and operative challenge. We report three cases of IDEPS and their surgical management, describing our experience and approach to such rare clinical entities. From 2016 to 2022, we treated 3 cases of IDEPS. Surgical techniques, histopathological findings and clinical outcomes were retrospectively evaluated for each case and compared. Three different surgical techniques were used to approach each lesion, from open thoracotomy to a combined laparoscopic and thoracoscopic approach. Histopathological analysis of the specimens revealed hybrid pathological features, proper of both congenital pulmonary airway malformation (CPAM) and extralobar pulmonary sequestration. IDEPS represent a surgical challenge for pediatric surgeons, given their complex surgical planning. In our experience, the thoracoscopic approach is safe and feasible when performed by trained surgeons, even though a combined thoracoscopic-laparoscopic approach allows for optimal vessels control. The presence of CPAM elements within the lesions supports their surgical removal. Additional studies are required to better characterize IDEPS and their management.

Prenatal ultrasound-and MRI-based imaging predictors of respiratory symptoms at birth for congenital lung malformations

BACKGROUND

Congenital lung malformations (CLM) are rare developmental anomalies of the fetal lung with a minority of patients exhibiting symptoms around the time of birth. Although ultrasound remains the gold standard, fetal MRI has recently been incorporated as an adjunct imaging modality in the workup and prenatal counseling of patients with CLM as it is thought to more accurately delineate lesion boundaries and diagnose lesion type. We evaluate what prenatal variables correlate with postnatal respiratory symptoms.

METHODS

We performed a retrospective review of patients with prenatal diagnosis of CLM treated at our institution between 2006-2020. Fetal ultrasound and magnetic resonance imaging (MRI) parameters including maximal congenital pulmonary airway malformation volume ratio (CVR), absolute cyst volume, and observed to expected normal fetal lung volume (O/E NFLV) were correlated with outcomes including postnatal respiratory symptoms, need for supplementary oxygen or mechanical ventilation, delay in tolerating full feeds, resection in the neonatal period.

RESULTS

Our study included 111 patients, all of whom underwent fetal ultrasound with 64 patients additionally undergoing fetal MRI. Postnatal respiratory symptoms were noted in 22.5% of patients, 19.8% required supplemental oxygen, 2.7% mechanical ventilation and two patients requiring urgent resection. Ultrasound parameters including absolute cyst volume and maximal CVR correlated with need for mechanical ventilation (p=0.034 and p=0.024, respectively) and for urgent resection (p=0.018 and p=0.023, respectively) and had a marginal association with postnatal respiratory symptoms (p=0.050 and p=0.052). Absolute cyst volume became associated with postnatal respiratory symptoms (p=0.017) after multivariable analysis controlling for maternal steroid administration and gestational age. O/E NFLV did not correlate with perinatal outcomes.

CONCLUSION

We have found that ultrasound-based measurements correlate with postnatal respiratory symptoms, while MRI derived O/E NFLV does not. Further studies are needed to elucidate the role of MRI in the prenatal workup of congenital lung malformations.

TYPE OF STUDY

Study of Diagnostic Test.

LEVEL OF EVIDENCE

Level I.

Challenges in DICER1-Associated Lung Disease

Pleuropulmonary blastoma (PPB) is a tumor occurring almost exclusively in infants and young children. This is the most common primary-lung malignancy in childhood. There is age-associated progression through a distinctive sequence of pathologic changes, from a purely multicystic lesion type I to a high-grade sarcoma type II and III. While complete resection is the cornerstone treatment for type I PPB, aggressive chemotherapy with a less favorable prognosis is associated with type II and III. DICER1 germline mutation is positive in 70% of children with PPB. Diagnosis is challenging, as it resembles congenital pulmonary airway malformation (CPAM) in imaging. Although PPB is an extremely rare malignancy, over the past five years we have encountered several children diagnosed with PPB in our medical center. Herein, we present some of these children and discuss diagnostic, ethical, and therapeutic challenges.

The natural history of prenatally diagnosed congenital pulmonary airway malformations and bronchopulmonary sequestrations

BACKGROUND

The natural history of congenital pulmonary airway malformations (CPAM) and bronchopulmonary sequestrations (BPS) is not fully understood, and the management of the newborn with an asymptomatic lesion is a controversial issue. We aimed to study the natural history and outcome of CPAM/BPS at our institution with a policy of watchful waiting, and to investigate if any prognostic factors in the pre- and/or postnatal- period may predict the need for surgery.

MATERIAL AND METHODS

A retrospective review study was conducted of children prenatally diagnosed with CPAM and/or BPS during the 18-year period, from 2002 to 2020. Data from the pre and postnatal period was collected and analysed.

RESULTS

Sixty- six patients with prenatally observed lung lesions were entered in the study, with an overall survival rate of 94%. Fifty-six percent of the lesions decreased in size during gestation. Thirty-one percent had surgery and 69% could be managed conservatively with a median follow-up of 4 years. Nineteen percent developed symptoms after the neonatal period. Children with a presence of mediastinal shift on postnatal imaging (p = 0.003), with a high CVR (p = 0.005) and a large lesion size during gestation (p = 0.014) were significantly more likely to require surgery.

CONCLUSION

Prenatal regression is common among prenatally diagnosed CPAM/BPS and the majority of children that are asymptomatic beyond the neonatal period will remain asymptomatic throughout their childhood. Future analysis with a longer follow-up might give new insights in order to identify children at risk of developing symptoms.

LEVEL OF EVIDENCE

III.

Proteomic methods identified P75 as marker of poor prognosis in pleuropulmonary blastoma

OBJECTIVES

To study the causes of the rapid progression of pleuropulmonary blastoma and to identify molecular markers related to its prognosis.

MATERIALS AND METHODS

Three pairs of fresh frozen samples of pleuropulmonary blastoma tumors and adjacent normal tissues were analyzed for proteomics, focusing on the protein molecules with significantly increased expression in tumor tissues and related to the cell cycle and DNA replication. The top five protein molecules were selected and verified by immunohistochemistry. To analyze the correlation between the expression of verified protein molecules in pleuropulmonary blastoma and early recurrence/metastasis of pleuropulmonary blastoma.

RESULTS

Compared with the adjacent normal tissues, 1759 proteins were upregulated and 967 proteins were downregulated in pleuropulmonary blastoma. The top five proteins related to the cell cycle and DNA replication were ORC2, P75, Skp2, MCM4 and PCNA. However, only P75, MCM4 and PCNA were upregulated in pleuropulmonary blastoma as determined by immunohistochemistry. Further analysis showed that the expression of P75 in the recurrence/metastasis group was significantly higher than that in the no recurrence/metastasis group, while the expression of MCM4 and PCNA was not significantly different between the recurrence/metastasis group and the no recurrence/metastasis group.

CONCLUSIONS

MCM4, PCNA and P75 may all play an important role in the progression of pleuropulmonary blastoma. Among them, P75 is related to the prognosis and may be used as a marker to predict the prognosis of pleuropulmonary blastoma.

Primary lung carcinoma in children and adolescents: An analysis of the European Cooperative Study Group on Paediatric Rare Tumours (EXPeRT)

BACKGROUND

Primary lung carcinoma is an exceptionally rare childhood tumour, as per definition of the European Cooperative Study Group on Paediatric Rare Tumours (EXPeRT), with an incidence of 0.1-0.2/1,000,000 per year. Little is known about the clinical characteristics of children with primary lung carcinoma, a gap which this joint analysis of the EXPeRT group aimed to fill.

PATIENTS AND METHODS

We performed a retrospective case series of children (aged 0-18 years) with primary lung carcinoma, as collected through the EXPeRT databases between 2000 and 2021. We recorded relevant clinical characteristics including treatment and outcome.

RESULTS

Thirty-eight patients were identified with a median age of 12.8 years at diagnosis (range: 0-17). Mucoepidermoid carcinoma (MEC) was the most frequent entity (n = 20), followed by adenocarcinoma (n = 12), squamous cell carcinoma (n = 4), adenosquamous carcinoma (n = 1) and small-cell lung cancer (n = 1). Patients with MEC presented rarely with lymph node metastases (2/20 cases). Overall, 19/20 patients achieved long-lasting remission by surgical resection only. Patients with other histologies often presented in advanced stages (14/18 TNM stage IV). With multimodal treatment, 3-year overall survival was 52% ± 13%. While all patients with squamous cell carcinoma died, the 12 patients with adenocarcinoma had a 3-year overall survival of 64% ± 15%.

CONCLUSIONS

Primary lung carcinomas rarely occur in children. While the outcome of children with MEC is favourable with surgery alone, patients with other histotypes have a poor prognosis, despite aggressive treatment, highlighting the need to develop new strategies for these children, such as mutation-guided treatment.

The Management of Asymptomatic Congenital Pulmonary Airway Malformation: Results of a European Delphi Survey

Consensus on the optimal management of asymptomatic congenital pulmonary airway malformation (CPAM) is lacking, and comparison between studies remains difficult due to a large variety in outcome measures. We aimed to define a core outcome set (COS) for pediatric patients with an asymptomatic CPAM. An online, three-round Delphi survey was conducted in two stakeholder groups of specialized caregivers (surgeons and non-surgeons) in various European centers. Proposed outcome parameters were scored according to level of importance, and the final COS was established through consensus. A total of 55 participants (33 surgeons, 22 non-surgeons) from 28 centers in 13 European countries completed the three rounds and rated 43 outcome parameters. The final COS comprises seven outcome parameters: respiratory insufficiency, surgical complications, mass effect/mediastinal shift (at three time-points) and multifocal disease (at two time-points). The seven outcome parameters included in the final COS reflect the diversity in priorities among this large group of European participants. However, we recommend the incorporation of these outcome parameters in the design of future studies, as they describe measurable and validated outcomes as well as the accepted age at measurement.

Accuracy of Chest Computed Tomography in Distinguishing Cystic Pleuropulmonary Blastoma From Benign Congenital Lung Malformations in Children

IMPORTANCE

The ability of computed tomography (CT) to distinguish between benign congenital lung malformations and malignant cystic pleuropulmonary blastomas (PPBs) is unclear.

OBJECTIVE

To assess whether chest CT can detect malignant tumors among postnatally detected lung lesions in children.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective multicenter case-control study used a consortium database of 521 pathologically confirmed primary lung lesions from January 1, 2009, through December 31, 2015, to assess diagnostic accuracy. Preoperative CT scans of children with cystic PPB (cases) were selected and age-matched with CT scans from patients with postnatally detected congenital lung malformations (controls). Statistical analysis was performed from January 18 to September 6, 2020. Preoperative CT scans were interpreted independently by 9 experienced pediatric radiologists in a blinded fashion and analyzed from January 24, 2019, to September 6, 2020.

MAIN OUTCOMES AND MEASURES

Accuracy, sensitivity, and specificity of CT in correctly identifying children with malignant tumors.

RESULTS

Among 477 CT scans identified (282 boys [59%]; median age at CT, 3.6 months [IQR, 1.2-7.2 months]; median age at resection, 6.9 months [IQR, 4.2-12.8 months]), 40 cases were extensively reviewed; 9 cases (23%) had pathologically confirmed cystic PPB. The median age at CT was 7.3 months (IQR, 2.9-22.4 months), and median age at resection was 8.7 months (IQR, 5.0-24.4 months). The sensitivity of CT for detecting PPB was 58%, and the specificity was 83%. High suspicion for malignancy correlated with PPB pathology (odds ratio, 13.5; 95% CI, 2.7-67.3; P = .002). There was poor interrater reliability (κ = 0.36 [range, 0.06-0.64]; P < .001) and no significant difference in specific imaging characteristics between PPB and benign cystic lesions. The overall accuracy rate for distinguishing benign vs malignant lesions was 81%.

CONCLUSIONS AND RELEVANCE

This study suggests that chest CT, the current criterion standard imaging modality to assess the lung parenchyma, may not accurately and reliably distinguish PPB from benign congenital lung malformations in children. In any cystic lung lesion without a prenatal diagnosis, operative management to confirm pathologic diagnosis is warranted.

Congenital lung lesions: a radiographic pattern approach

Congenital lung malformations represent a spectrum of abnormalities that can overlap in imaging appearance and frequently coexist in the same child. Imaging diagnosis in the neonatal period can be challenging; however, the recognition of several archetypal radiographic patterns can aid in narrowing the differential diagnosis. Major radiographic archetypes include (1) hyperlucent lung, (2) pulmonary cysts, (3) focal opacity and (4) normal radiograph. Here we review the multimodality imaging appearances of the most commonly seen congenital lung malformations, categorized by their primary imaging archetypes. Along with the congenital lung malformations, we present several important imaging mimickers.

DICER1 tumor predisposition syndrome: an evolving story initiated with the pleuropulmonary blastoma

DICER1 syndrome (OMIM 606241, 601200) is a rare autosomal dominant familial tumor predisposition disorder with a heterozygous DICER1 germline mutation. The most common tumor seen clinically is the pleuropulmonary blastoma (PPB), a lung neoplasm of early childhood which is classified on its morphologic features into four types (IR, I, II and III) with tumor progression over time within the first 4-5 years of life from the prognostically favorable cystic type I to the unfavorable solid type III. Following the initial report of PPB, its association with other cystic neoplasms was demonstrated in family studies. The detection of the germline mutation in DICER1 provided the opportunity to identify and continue to recognize a number seemingly unrelated extrapulmonary neoplasms: Sertoli-Leydig cell tumor, gynandroblastoma, embryonal rhabdomyosarcomas of the cervix and other sites, multinodular goiter, differentiated and poorly differentiated thyroid carcinoma, cervical-thyroid teratoma, cystic nephroma-anaplastic sarcoma of kidney, nasal chondromesenchymal hamartoma, intestinal juvenile-like hamartomatous polyp, ciliary body medulloepithelioma, pituitary blastoma, pineoblastoma, primary central nervous system sarcoma, embryonal tumor with multilayered rosettes-like cerebellar tumor, PPB-like peritoneal sarcoma, DICER1-associated presacral malignant teratoid neoplasm and other non-neoplastic associations. Each of these neoplasms is characterized by a second somatic mutation in DICER1. In this review, we have summarized the salient clinicopathologic aspects of these tumors whose histopathologic features have several overlapping morphologic attributes particularly the primitive mesenchyme often with rhabdomyoblastic and chondroid differentiation and an uncommitted spindle cell pattern. Several of these tumors have an initial cystic stage from which there is progression to a high grade, complex patterned neoplasm. These pathologic findings in the appropriate clinical setting should serve to alert the pathologist to the possibility of a DICER1-associated neoplasm and initiate appropriate testing on the neoplasm and to alert the clinician about the concern for a DICER1 mutation.

Pleuropulmonary Blastoma (PPB) in Child with DICER1 Mutation: The First Case Report in the State of Qatar

Pleuropulmonary blastoma (PPB) is a rare intrathoracic malignancy, which arises from the lung parenchyma and/or pleura. PPB has strong genetic association with mutations in DICER1 gene. Despite being rare, PPB is the most common lung tumor in children below 6 years of age. International registry of the disease has a total of 350 cases worldwide. We report the first case of PPB in the state of Qatar, which presented as a large cystic lung lesion. The patient was first thought to have benign congenital pulmonary airway malformation (CPAM) based on chest X-ray findings. The diagnosis of PPB was suspected based on chest CT scan findings and was confirmed after surgical resection of the cystic mass. The case highlights the need to consider PPB in the differential diagnosis of cystic lung lesions in children and the need for further radiological imaging (i.e., CT scan), genetic testing, and/or excisional biopsy to confirm the diagnosis.

SARS-CoV-2 Exposed Mesenchymal Stromal Cell from Congenital Pulmonary Airway Malformations: Transcriptomic Analysis and the Expression of Immunomodulatory Genes

The inflammatory response plays a central role in the complications of congenital pulmonary airway malformations (CPAM) and severe coronavirus disease 2019 (COVID-19). The aim of this study was to evaluate the transcriptional changes induced by SARS-CoV-2 exposure in pediatric MSCs derived from pediatric lung (MSCs-lung) and CPAM tissues (MSCs-CPAM) in order to elucidate potential pathways involved in SARS-CoV-2 infection in a condition of exacerbated inflammatory response. MSCs-lung and MSCs-CPAM do not express angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TRMPSS2). SARS-CoV-2 appears to be unable to replicate in MSCs-CPAM and MSCs-lung. MSCs-lung and MSCs-CPAM maintained the expression of stemness markers MSCs-lung show an inflammatory response (IL6, IL1B, CXCL8, and CXCL10), and the activation of Notch3 non-canonical pathway; this route appears silent in MSCs-CPAM, and cytokine genes expression is reduced. Decreased value of p21 in MSCs-lung suggested no cell cycle block, and cells did not undergo apoptosis. MSCs-lung appears to increase genes associated with immunomodulatory function but could contribute to inflammation, while MSCs-CPAM keeps stable or reduce the immunomodulatory receptors expression, but they also reduce their cytokines expression. These data indicated that, independently from their perilesional or cystic origin, the MSCs populations already present in a patient affected with CPAM are not permissive for SARS-CoV-2 entry, and they will not spread the disease in case of infection. Moreover, these MSCs will not undergo apoptosis when they come in contact with SARS-CoV-2; on the contrary, they maintain their staminality profile.

Atypical Antenatal Presentation of an Unusual Nonmucinous Papillary Variant of Giant Congenital Pulmonary Airway Malformation Masquerading as Congenital Diaphragmatic Hernia with Volvulus

We report a case of a huge congenital pulmonary airway malformation (CPAM) that was referred as congenital diaphragmatic hernia (CDH). Initial ultrasound evaluation revealed a huge cystic lesion with septations, in the thorax, causing mediastinal shift and compression effects, suggesting the possibility of a thoracic lymphangioma, or bowel herniation with obstruction. A fetal magnetic resonance imaging reported possible bowel herniation through a posterior defect in the diaphragm, with volvulus, reinforcing the diagnosis of CDH. It was only on autopsy and subsequent histopathology examination that the diagnosis of a rare variant of CPAM-nonmucinous papillary type, could be made. To the best of our knowledge, a CPAM this huge has not been reported prenatally at this gestation. We recommend considering the potential diagnosis of CPAM in any thoracic cystic irrespective of its size or appearance.

Thoracoscopic segmentectomy for a large previously undiagnosed CPAM presenting as a spontaneous pneumothorax: A case report

Introduction

Incidentally found congenital pulmonary airway malformations (CPAM) in older children are extremely rare and have traditionally been managed with minimally invasive versus open lobectomy of the affected lobe.

Presentation of case

In this report, we present a 11-year-old male who presented with a recurrent spontaneous pneumothorax and was found to have a large symptomatic CPAM confined to a single segment of the right lower lobe. The patient was successfully treated with thoracoscopic segmentectomy without any residual disease seen on follow up imaging.

Discussion

Minimally invasive thoracoscopic approach has many advantages over open approach including better pain control, reduced hospital length of stay, and decreased intraoperative blood loss. With increasing use of minimally invasive approaches, lung-sparing surgery has demonstrated to be a viable and an attractive option for definitive resection of CPAM, without compromising resection margins and/or future lung function.

Conclusion

This report demonstrates that minimally invasive lung-sparing surgical treatment of a large CPAM is feasible in older children.

•

Older children with CPAM can present with a spontaneous pneumothorax.

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CPAM confined to a segment of a single lobe should be managed with segmentectomy.

•

VATS segmentectomy for CPAM in older children can be successful.

A rare case report of simultaneous occurrence of a pediatric pleuropulmonary blastoma and an intralobar pulmonary sequestration

We are presenting a rare case with the simultaneous occurrence of pleuropulmonary blastoma and an intra lobar pulmonary sequestration. Although there have been cases reported previously with pleuropulmonary blastoma associated with congenital pulmonary malformations, the association with an intra lobar pulmonary sequestration is very rare. The patient, a female, 6-month-old child arrived at our pediatric service with the clinic of cough, respiratory distress, and fever after being treated for 2 weeks for left lung bronchopneumonia according clinical signs and radiographic description but without clinical improvements. Contrast enhanced CT images showed the simultaneous presence of 2 different lesions in the left lung, a heterogeneous mass in the superior lobe without delineation with mediastinal structure compatible with a pleuropulmonary blastoma and a consolidation in the inferior lobe with bronchogram present and a systemic vessel feeding compatible with an intra lobar pulmonary sequestration, both confirmed by histologic examinations after the surgical intervention. Although it is very rare, the simultaneous presence of these distinct embryogenic lesions may occur and radiologist should be aware as the imaging diagnosis may be very helpful for the further management of the patient.

Multimodality treatment including whole pleura radiation therapy for DICER1-associated pediatric pleuropulmonary blastoma

Limited data are available regarding radiation therapy in pediatric pleuropulmonary blastoma (PPB). We report the case of a 3-year-old girl with type II PPB successfully treated with trimodality therapy including multiagent chemotherapy, resection, and whole pleura radiation therapy. While longer follow-up is required to confirm ultimate local tumor control and long-term post-treatment sequelae, currently 3.5 years following therapy, she is well, without recurrent disease or observable toxicity. The goal of this report is to add our experience to the literature regarding PPB, its management, and treatment, as prospective randomized controlled trials are not feasible due to the rarity of this disease.

Is It Better to Operate Congenital Lung Malformations when Patients are Still Asymptomatic?

Context:

Congenital lung malformation (CLM) is a rare developmental anomaly of the lower respiratory tract. The purposes are to define if the presence of respiratory symptoms, in CLM may affect surgical outcomes and to define optimal timing for surgery in asymptomatic patients.

Settings and Design:

Retrospective review of patients with CLM from 2004 to 2018. Asymptomatic and symptomatic patients were compared. Moreover, asymptomatic patients were stratified according to age at surgery (< or >6 months).

Subjects and Methods:

Demographic data, prenatal diagnosis, symptoms, CLM's characteristics, operative and postoperative data were collected. Patients were divided into two groups based on the presence or none of respiratory symptoms.

Statistical Analysis:

Data were compared using the Fisher's exact test for qualitative values and Mann-Whitney test for quantitative values P < 0.05 was statistically significant.

Results:

One hundred and eighty-six patients were treated. Asymptomatic were 137 (74%), while symptomatic were 49 (26%). The most common presenting symptoms were respiratory distress (n = 30, 61%) followed by pneumonia (n = 18, 38%). Prenatal diagnosis of CLM was performed in 98% of asymptomatic patients compared to 30% of symptomatic (P = 0.001). Surgical excision was performed in all cases, and in 50% by thoracoscopy, without difference between the two groups. In 97% of all cases, a lung sparing surgery was performed without difference between the groups. Symptoms are significantly associated with older age, location in the upper lobe, and lobar emphysema. Length of stay in intensive care, postoperative complications, and reintervention rate were higher in the symptomatic group. Eighty-one asymptomatic patients underwent surgery <6 months of life; they had a lower rate of surgical complications (2%) compared with those >6 months (7%).

Conclusions:

The present study describes a comprehensive picture of CLM. In addition, we emphasize the role of early postnatal management and thoracoscopic surgery, also before 6 months of life, to prevent the onset of symptoms that are associated with worse outcomes.

Morbidity after thoracoscopic resection of congenital pulmonary airway malformations (CPAM): single center experience over a decade

PURPOSE

Video-assisted thoracoscopic (VATS) resection of CPAM in children is an established, albeit controversial strategy for its management. We report a 10-year single center experience.

METHODS

All children underwent VATS (2008-2017) and their current status was reviewed. Patients were grouped: 'symptomatic-P' (if parents reported recurrent lower respiratory tract infections etc.) or 'symptomatic-S' (neonates presenting with respiratory distress/difficulty) or 'asymptomatic'.

RESULTS

73 children, aged 10 m (4d-14yrs) underwent VATS; a neonate as an emergency ('symptomatic-S') and all others electively. The lesion was unilateral in all but one case. Histologically none were malignant. Of the elective 72 cases, 7 (10%) required conversion to open thoracotomy. Twenty (27.7%) were 'symptomatic-P' and the duration of surgery when compared to 'asymptomatic' children was longer 269 (range 129-689) versus 178 (range 69-575) minutes (P = 0.01). Post operatively, 8 children (11%) had a grade III/IV (Clavien-Dindo) complication; persistent air leak/pneumothorax (n = 5), chylothorax (n = 1), pleural effusion (n = 1) and seizure/middle cerebral artery thrombosis (n = 1). There was no mortality. Twenty-four children (33.3%) were reported 'symptomatic-P' post-surgery after a median follow up of 2.18 years. The surgical intervention had no impact on 'symptomatic-P' status (P = 0.46).

CONCLUSION

The risks of surgery may outweigh benefit in asymptomatic children. CLINICALTRIALS.

GOV IDENTIFIER

NCT04449614.

Abrogation of mesenchyme-specific TGF-β signaling results in lung malformation with prenatal pulmonary cysts in mice

The TGF-β signaling pathway plays a pivotal role in controlling organogenesis during fetal development. Although the role of TGF-β signaling in promoting lung alveolar epithelial growth has been determined, mesenchymal TGF-β signaling in regulating lung development has not been studied in vivo due to a lack of genetic tools for specifically manipulating gene expression in lung mesenchymal cells. Therefore, the integral roles of TGF-β signaling in regulating lung development and congenital lung diseases are not completely understood. Using a Tbx4 lung enhancer-driven Tet-On inducible Cre transgenic mouse system, we have developed a mouse model in which lung mesenchyme-specific deletion of TGF-β receptor 2 gene (Tgfbr2) is achieved. Reduced airway branching accompanied by defective airway smooth muscle growth and later peripheral cystic lesions occurred when lung mesenchymal Tgfbr2 was deleted from embryonic day 13.5 to 15.5, resulting in postnatal death due to respiratory insufficiency. Although cell proliferation in both lung epithelium and mesenchyme was reduced, epithelial differentiation was not significantly affected. Tgfbr2 downstream Smad-independent ERK1/2 may mediate these mesenchymal effects of TGF-β signaling through the GSK3β-β-catenin-Wnt canonical pathway in fetal mouse lung. Our study suggests that Tgfbr2-mediated TGF-β signaling in prenatal lung mesenchyme is essential for lung development and maturation, and defective TGF-β signaling in lung mesenchyme may be related to abnormal airway branching morphogenesis and congenital airway cystic lesions.

Pleuropulmonary Blastoma in Pediatric Lung Lesions

BACKGROUND

Pediatric lung lesions are a group of mostly benign pulmonary anomalies with a broad spectrum of clinical disease and histopathology. Our objective was to evaluate the characteristics of children undergoing resection of a primary lung lesion and to identify preoperative risk factors for malignancy.

METHODS

A retrospective cohort study was conducted by using an operative database of 521 primary lung lesions managed at 11 children's hospitals in the United States. Multivariable logistic regression was used to examine the relationship between preoperative characteristics and risk of malignancy, including pleuropulmonary blastoma (PPB).

RESULTS

None of the 344 prenatally diagnosed lesions had malignant pathology (P < .0001). Among 177 children without a history of prenatal detection, 15 (8.7%) were classified as having a malignant tumor (type 1 PPB, n = 11; other PPB, n = 3; adenocarcinoma, n = 1) at a median age of 20.7 months (interquartile range, 7.9-58.1). Malignancy was associated with the DICER1 mutation in 8 (57%) PPB cases. No malignant lesion had a systemic feeding vessel (P = .0427). The sensitivity of preoperative chest computed tomography (CT) for detecting malignant pathology was 33.3% (95% confidence interval [CI]: 15.2-58.3). Multivariable logistic regression revealed that increased suspicion of malignancy by CT and bilateral disease were significant predictors of malignant pathology (odds ratios of 42.15 [95% CI, 7.43-340.3; P < .0001] and 42.03 [95% CI, 3.51-995.6; P = .0041], respectively).

CONCLUSIONS

In pediatric lung masses initially diagnosed after birth, the risk of PPB approached 10%. These results strongly caution against routine nonoperative management in this patient population. DICER1 testing may be helpful given the poor sensitivity of CT for identifying malignant pathology.

Obstetrician patterns of steroid administration for the prenatal management of congenital pulmonary airway malformations

BACKGROUND

Congenital pulmonary airway malformation (CPAM) is the most common prenatally-diagnosed lung malformation. This lesion, classified as macrocystic or microcystic, can lead to significant fetal compromise. Management options include observation, maternal antenatal steroid administration, and fetal surgical intervention. Current evidence suggests that microcystic (but not macrocystic) lesions and those with a cyst volume ratio (CVR) >1.6 are responsive to steroid therapy. The objective of this study was to identify patterns of prenatal steroid administration for the management of CPAMs and to identify characteristics of CPAMs prompting steroid administration.

METHODS

An 18-question survey was distributed to obstetricians from the Pregnancy-Related Care Research Network (PRCRN) and the North American Fetal Therapy Network (NAFTNet), from January to April 2019, to capture antenatal steroid prescribing patterns.

RESULTS

Response rates were 28.3% (138/487) for PRCRN and 63.3% (19/30) for NAFTNet. Among PRCRN members, 16.8% administered prenatal steroids, with most (77.2%) doing so for both microcystic and macrocystic CPAMs; corresponding percentages for NAFTNet members were 90.9% and 52.6%. Two thirds (65.6%) of obstetricians who administer steroids do so for a CVR > 1.6, without evidence of mediastinal shift or hydrops fetalis.

CONCLUSIONS

There is a lack of consensus among obstetricians as to the CPAM characteristics that should prompt administration of prenatal steroids. Many surveyed obstetricians do not use cyst type or CVR to guide decision-making regarding steroid therapy.

Pleuropulmonary Blastoma with Hotspot Mutations in RNase IIIb Domain of DICER 1: Clinicopathologic Study of 10 Cases in a Single-Institute Experience

INTRODUCTION

Pleuropulmonary blastoma (PPB) is a rare sarcomatous malignancy involving the lung and pleura which occurs in early childhood. Cystic PPB in the early stage can be misdiagnosed as other cystic diseases. Early detection of this entity is important for appropriate treatment and prevention of disease progression. Hotspot mutations in the ribonuclease IIIb (RNase IIIb) domain of DICER1 have been reported to have a crucial role as genetic factors of PPB and DICER1 familial syndrome. We reviewed the clinicopathologic findings of PPB and the status of DICER1 hotspot mutation and patients' clinical course.

METHODS

We retrospectively reviewed all patients with histologically confirmed PPB at Asan Medical Center between 2000 and 2017. Ten cases were identified in the database, and their clinicopathologic parameters were evaluated. PPB was classified into the following 3 pathologic subtypes: type I (purely cystic), type II (mixed cystic and solid), and type III (entirely solid). The status of DICER1 mutation in 2 hotspot regions of the RNase IIIb domain was evaluated by Sanger sequencing.

RESULTS

The most frequent PPB type was II (6 cases), followed by I and III (2 cases each). The age at diagnosis ranged from 16 months to 15 years. All patients underwent surgery, and all patients received adjuvant or neoadjuvant chemotherapy. Four of 7 patients had missense mutations in the RNase IIIb hotspot; the base and predicted corresponding amino acid changes were c.5113 G>A (p.E1705K), c.5407 G>A (p.E1803K), c.5425 G>A (p.G1809R), and c.5428 G>T (p.D1810Y). There was no particular association between the presence of the hotspot mutation and histologic type. Nine patients survived with no evidence of disease for a median interval of 93 (range, 13-199) months. Only 1 patient diagnosed with type III PPB at the age of 18 years had recurrence after 20.8 months and eventually died 66 months after the initial diagnosis.

CONCLUSIONS

Late detection of solid PPB is associated with poor prognosis. Considering the rarity of PPB disease and the importance of DICER1 hotspot mutation in pathogenesis, DICER1 hotspot mutation testing and identification in the early cystic stage can improve patient outcomes.

Preoperative Embolization Facilitates Segmental Resection of Pulmonary Sequestration in an Infant

The most common congenital lung malformations are congenital pulmonary airway malformations and pulmonary sequestrations. Many surgeons advocate resection to prevent complications of infection, malignancy, and pneumothorax. The standard of care is lobectomy, but segmentectomy and embolization alone have been reported. These methods avoid the complications of lobectomy but are not widely practiced due to concerns about incomplete resection or involution of the lesion. We present a novel approach to the treatment of a pulmonary sequestration in a 7-month-old male using preoperative embolization followed by a sublobar pulmonary resection. The embolization clearly demarcated the affected lung intraoperatively, thereby facilitating complete removal of the lesion with a segmental lung resection rather than complete lobectomy.

DICER1 Syndrome and Cancer Predisposition: From a Rare Pediatric Tumor to Lifetime Risk

DICER1 syndrome is a rare genetic condition predisposing to hereditary cancer and caused by variants in the DICER1 gene. The risk to present a neoplasm before the age of 10 years is 5.3 and 31.5% before the age of 60. DICER1 variants have been associated with a syndrome involving familial pleuropulmonary blastoma (PPB), a rare malignant tumor of the lung, which occurs primarily in children under the age of 6 years and represents the most common life-threatening manifestation of DICER1 syndrome. Type I, II, III, and Ir (type I regressed) PPB are reported with a 5-year overall survival ranging from 53 to 100% (for type Ir). DICER1 gene should be screened in all patients with PPB and considered in other tumors mainly in thyroid neoplasms (multinodular goiter, thyroid cancer, adenomas), ovarian tumors (Sertoli-Leydig cell tumor, sarcoma, and gynandroblastoma), and cystic nephroma. A prompt identification of this syndrome is necessary to plan a correct follow-up and screening during lifetime.

Programmed Death Ligand 1 Expression and Related Markers in Pleuropulmonary Blastoma

INTRODUCTION

Pleuropulmonary blastoma (PPB), a rare childhood neoplasm of the lung, is linked to pathogenic DICER1 variants. We investigated checkpoint inhibitor markers including Programmed Death Ligand 1 (PD-L1), PD1, CD8 and tumor mutational burden (TMB) in PPB.

MATERIAL AND METHODS

Cases were collected from departmental archives and the International PPB/DICER1 Registry. Immunohistochemistry (IHC) for PD-L1, PD-1, CD8 and DNA mismatch repair (MMR) genes were performed. In addition, normal-tumor paired whole exome sequencing (WES) was performed in two cases.

RESULTS

Twenty-five PPB cases were studied, consisting of Type I (n = 8, including 2 Ir), Type II (n = 8) and Type III (n = 9). PD-L1 combined positive score (CPS) of 1, 4 and 80 was seen in three (3/25, 12.0%) cases of Type II PPB with negative staining in the remaining cases. PD-1 and CD8 stains demonstrated positive correlation (P < .05). The density of PD1 and CD8 in the interface area was higher than within tumor (P < .05). The MMR proteins were retained. TMB was 0.65 mutations/Mb in type II PPB with high expression of PD-L1, and 0.94 mutations/Mb in one negative PD-L1 case with metastatic tumor.

CONCLUSION

A small subpopulation of PPB patient might benefit from checkpoint immunotherapy due to positive PD-L1 staining.

Congenital lung abnormality quantification by computed tomography: The CLAQ method

INTRODUCTION

To date, no consensus has been reached on the optimal management of congenital lung abnormalities, and factors predicting postnatal outcome have not been identified. We developed an objective quantitative computed tomography (CT) scoring method, and assessed its value for clinical decision-making.

METHODS

Volumetric CT-scans of all patients born with a congenital lung abnormality between January 1999 and 2018 were assessed. Lung disease was quantified using the newly-developed congenital lung abnormality quantification (CLAQ) scoring method. In 20 equidistant axial slices, cells of a square grid were scored according to the abnormality within. The scored CT parameters were used to predict development of symptoms, and SD scores for spirometry and exercise tolerance (Bruce treadmill test) at 8 years of age.

RESULTS

CT-scans of 124 patients with a median age of 5 months were scored. Clinical diagnoses included congenital pulmonary airway malformation (49%), bronchopulmonary sequestration (27%), congenital lobar overinflation (22%), and bronchogenic cyst (1%). Forty-four patients (35%) developed symptoms requiring surgery of whom 28 (22%) patients became symptomatic before a CT-scan was scheduled. Lesional hyperdensity was found as an important predictor of symptom development and decreased exercise tolerance. Using receiver operating characteristic analysis, an optimal cut-off value for developing symptoms was found at 18% total disease.

CONCLUSION

CT-quantification of congenital lung abnormalities using the CLAQ method is an objective and reproducible system to describe congenital lung abnormalities on chest CT. The risk for developing symptoms may increase when more than a single lung lobe is affected.

Pediatric Cystic Lung Lesions: Where Are We Now?

Pediatric cystic lung lesions have long been a source of confusion for clinicians, radiologists, and pathologists. They encompass a wide spectrum of entities with variable prognostic implications, including congenital lung malformations, pulmonary neoplasms, and hereditary conditions. As our understanding of the developmental and genetic origins of these conditions has evolved, revised nomenclature and classifications have emerged in an attempt to bring clarity to the origin of these lesions and guide clinical management. This review discusses cystic lung lesions and the current understanding of their etiopathogenesis.

Hydropneumothorax Revealing a Pneumoblastoma in Children

Pneumoblastoma is a rare primary childhood tumor. We report the observation of an infant aged 2 years and 8 months who presented with dry cough and dyspnea. The physical examination found mixed pleural effusion syndrome on the right. The chest X-ray revealed a right pneumothorax. Biology has shown leukocytosis at 16,000/mm³. The CT scan revealed parenchymal air cystic lesions affecting the outer segment of the middle lobe mimicking a pulmonary malformation. Thoracic drainage brought back 100 ml of the fluid. Two months later, when a pyopneumothorax appeared, a medium lobectomy was performed. Pathological study specimen showed a high-grade type II pneumoblastoma The extension assessment identified a secondary hepatic location. Chemotherapy has been indicated. This observation illustrates the diagnosis challenge of pneumoblastoma in children.

Epidemiological features and survival outcomes in patients with malignant pulmonary blastoma: a US population-based analysis

BACKGROUND

Pulmonary blastoma (PB) is a rare lung primary malignancy with poorly understood risk factors and prognosis. We sought to investigate the epidemiologic features and long-term outcomes of PB.

METHODS

A population-based cohort study was conducted to quantify the death risk of PB patients. All subjects diagnosed with malignant PB from 1988 to 2016 were screened from the Surveillance, Epidemiology and End Results database. Cox regression model of all-cause death and competing risk analysis of cause-specific death were performed.

RESULTS

We identified 177 PB patients with a median survival of 108 months. The 5 and 10-year survival rate in all PB patients were 58.2 and 48.5%, as well as the 5 and 10-year disease-specific mortality were 33.5 and 38.6%. No sex or race disparities in incidence and prognosis was observed. The death risk of PB was significantly associated with age at diagnosis, clinical stage, histologic subtype and surgery treatment (p<0.01). On multivariable regression analyses, older age, regional stage and no surgery predicted higher risk of both all-cause and disease-specific death in PB patients.

CONCLUSION

We described the epidemiological characteristics of PB and identified its prognostic factors that were independently associated with worse clinical outcome.

Early KRAS oncogenic driver mutations in nonmucinous tissue of congenital pulmonary airway malformations as an indicator of potential malignant behavior

The potential for malignant degeneration is the most common reason for some practitioners to resect asymptomatic congenital pulmonary airway malformations (CPAMs). We aimed to investigate the potential of various immunohistochemical (IHC) and genomic biomarkers to predict the presence of mucinous proliferations (MPs) in CPAM. Archival CPAM tissue samples were re-assessed and underwent IHC analysis using a panel of differentiating markers (TTF1/CDX2/CC10/MUC2/MUC5AC/p16/p53/DICER1). In each sample, intensity of IHC staining was assessed separately in normal lung tissue, CPAM, and MP tissue, using a semiquantitative approach. Likewise, next-generation targeted sequencing of known adult lung driver mutations, including KRAS/BRAF/EGFR/ERBB2, was performed in all samples with MP and in control samples of CPAM tissue without MP. We analyzed samples of 25 CPAM type 1 and 25 CPAM type 2 and found MPs in 11 samples. They were all characterized by strong MUC5AC expression, and all carried a KRAS mutation in the MP and adjacent nonmucinous CPAM tissue, whereas the surrounding normal lung tissue was negative. By contrast, in less than half (5 out of 12) control samples lacking MP, the CPAM tissue also carried a KRAS mutation. KRAS mutations in nonmucinous CPAM tissue may identify lesions with a potential for malignant degeneration and may guide histopathological assessment and patient follow-up.

The future is here: Integrating genetics into the pediatric pulmonary clinic

Recognition of underlying genetic etiologies of disease is increasing at an exponential rate, likely due to greater access to and lower cost of genetic testing. Monogenic causes of disease, or conditions resulting from a mutation or mutations in a single gene, are now well recognized in every subspecialty, including pediatric pulmonary medicine; thus, it is important to consider genetic conditions when evaluating children with respiratory disease. In the pediatric pulmonary clinic, genetic testing should be considered when multiple family members present with similar or related clinical features and when individuals have unusual clinical presentations, such as early-onset disease or complex, syndromic features. This review provides a practical guide for genetic diagnosis in the pediatric pulmonary setting, including a review of genetic concepts, considerations for test selection and results in interpretation, as well as an overview of genetic differential diagnoses for common pediatric pulmonary phenotypes. Genetic conditions that commonly present to the pediatric pulmonary clinic are reviewed in a companion article by Yonker et al.

Fluid-filled Cystic Lesions of the Lungs

A pulmonary cyst usually refers to an air-filled space with a smooth, thin wall. Fluid-filled cystic lesions of the lungs include a range of etiologies such as true cysts, congenital malformations, infections, and benign and malignant neoplasms. With relatively little solid component, these lesions often have similar imaging appearances to one another. This article focuses on key imaging features and clinical characteristics that can be used to narrow the differential diagnosis.

An update on the central nervous system manifestations of DICER1 syndrome

DICER1 syndrome is a rare tumor predisposition syndrome with manifestations that predominantly affect children and young adults. The syndrome is typically caused by heterozygous germline loss-of-function DICER1 alterations accompanied on the other allele by somatic missense mutations occurring at one of a few mutation hotspots within the sequence encoding the RNase IIIb domain. DICER1 encodes a member of the microRNA biogenesis machinery. The syndrome spectrum is highly pleiotropic and features a unique constellation of benign and malignant neoplastic and dysplastic lesions. Pleuropulmonary blastoma (PPB), the most common primary lung cancer in children, is the hallmark tumor of the syndrome. Other manifestations include ovarian Sertoli-Leydig cell tumor, cystic nephroma arising in childhood, multinodular goiter, thyroid carcinoma, anaplastic sarcoma of the kidney, embryonal rhabdomyosarcoma, and nasal chondromesenchymal hamartoma, in addition to other rare entities. Several central nervous system (CNS) manifestations have also been defined, including metastases of PPB to the cerebrum, pituitary blastoma, pineoblastoma, ciliary body medulloepithelioma, and most recently primary DICER1-associated CNS sarcomas and ETMR-like infantile cerebellar embryonal tumor. Macrocephaly is a recently reported non-neoplastic, haploinsufficient phenotype. In this manuscript, we review the CNS manifestations of DICER1 syndrome.

Pleuropulmonary blastoma type I might arise in congenital pulmonary airway malformation type 4 by acquiring a Dicer 1 mutation

Congenital pulmonary airway malformation (CPAM) occurs most commonly in infants. It is divided into 5 types. The most common types 1 and 2 are cystic, type 0 presents as bronchial buds without alveolar tissue, most likely corresponding to alveolar dysgenesis, while type 3 is composed of branching bronchioles and appears as a solid lesion. A defect in the epithelial-mesenchymal crosstalk might be the underlying mechanism for all. Type 4 is a peripheral cystic lesion with a thin cyst wall covered by pneumocytes. CPAM 4 has been mixed up with pleuropulmonary blastoma (PPB) type I and some authors question its existence. We investigated five cases of CPAM type 4 for the presence or absence of rhabdomyoblasts, and for markers associated with CPAM development. In addition, all cases were evaluated for mutations within the Dicer gene and for mutations of the RAS family of oncogenes. All five cases showed smooth muscle actin and desmin-positive cells; however, only one case showed a few cells positive for MyoD. The same case showed a mutation of Dicer 1. All cases were negative for mutations of the RAS family of genes. Fibroblast growth factor 10 was similarly expressed in all cases, and thus cannot be used to differentiate CPAM4 from PPB-I. Low expression of the proliferation marker Ki67 was seen in our CPAM 4 cases and the probable PPB-I case. YingYang-1 protein seems to play an active role in the development of PPB-I. CPAM 4 can be separated from PPB-I based on the presence of rhabdomyoblasts and mutations in Dicer 1 gene. These cells might not be numerous; therefore, all available tissue has to be evaluated. As CPAM 4 morphologically looks very similar to PPB-I, it might be speculated, that there exists a potential for progression from CPAM 4 to PPB-I, by acquiring somatic mutations in Dicer 1.

Pleuropulmonary blastoma: A report of two cases

Pleuropulmonary blastoma is a rare and aggressive childhood tumor of mesenchymal origin. It has a poor prognosis and mainly classified as cystic (type 1), mixed type (type 2), and solid (type 3). Herein, we present two cases of pleuropulmonary blastoma type 3 presenting with pneumothorax, a rare clinical presentation of pleuropulmonary blastoma, which was successfully treated with surgery.

Type I pleuropulmonary blastoma presenting as congenital pulmonary airway malformation: A report of two cases

Pleuropulmonary blastoma (PPB) is a rare aggressive intrathoracic tumor which is believed to originate from embryonic uncommitted lung mesenchymal cells, which are important for developing the lung. Type I PPB is cystic, type II is cystic and solid, while type III is predominantly solid. Diagnosing type 1 PPB is a challenge for both radiologists as well as pathologists. Owing to its purely cystic nature, type I PPB it is often mistaken for unrelated entities such as congenital pulmonary airway malformation and congenital lobar emphysema which delays surgical intervention. Here, we report two such cases presenting clinically and radiologically as congenital pulmonary airway malformation. On histology, a final diagnosis of type I pleuropulmonay blastoma was made. Thereafter, chemotherapy was administered following complete surgical excision.