Prenatal presentation and outcome of children with pleuropulmonary blastoma

Positron emission tomography in the diagnosis and management of primary pediatric lung tumors

Primary pediatric lung tumors are uncommon and have many overlapping clinical and imaging features. In contrast to adult lung tumors, these rare pediatric neoplasms have a relatively broad histologic spectrum. Informed by a single-institution 13-year retrospective record review, we present an overview of the most common primary pediatric lung neoplasms, with a focus on the role of positron emission tomography (PET), specifically 18F-fluorodeoxyglucose (FDG) PET and 68Ga-DOTATATE PET, in the management of primary pediatric lung tumors. In addition to characteristic conventional radiographic and cross-sectional imaging findings, knowledge of patient age, underlying cancer predisposition syndromes, and PET imaging features may help narrow the differential. While metastases from other primary malignancies remain the most commonly encountered pediatric lung malignancy, the examples presented in this pictorial essay highlight many of the important conventional radiologic and PET imaging features of primary pediatric lung malignancies.

Can we predict the need for postnatal surgery in patients with prenatal fetal lung masses detected by CVR value?

AIM

The purpose of this study is to evaluate whether CPAM-volume ratio (CVR) can predict postnatal management (follow up for resolution and surgical treatment) in fetuses with fetal lung masses in the prenatal period.

MATERIALS AND METHODS

44 patients who presented at our center with prenatally diagnosed CPAM (Congenital Pulmonary Airway Malformation) and BPS (Bronchopulmonary Sequestration) were analyzed. Obstetric history and outcomes, karyotype results, CVR, additional sonographic findings, characteristics of masses were recorded. CVR was calculated for all cases. İn the study we sought to identify a CVR threshold and did not use the thresholds classically used in the literature.

RESULTS

20 fetal BPS and 24 CPAM cases were analyzed. After excluding 5 patients, 46% of the patients were diagnosed with BPS and 54% with CPAM. İn this study the cut off < 0,53 for CVR is taken, it predicts the no need for postnatal surgery with a sensitivity of 85% and a specificity of 88%. When we take the > 0,76 cut-off value for patients who will require emergency surgery within the first 10 days, it predicts the need for surgery with 90% sensitivity and 89% specificity. In addition, it was determined that all patients with mediastinal shift were operated.

CONCLUSION

We believe that the CVR value and the presence of mediastinal shift should be evaluated in all cases of CPAM and BPS for prediction of the surgery. Proper counseling about the prognosis could be given to the family in cases with mediastinal shift and CVR value above 0,76.

A rare case of pleuropulmonary blastoma detected in fetus

Pleuropulmonary blastoma (PPB) is among the rarest malignant tumors diagnosed in children. PPBs can be histopathologically classified into 3 types: cystic tumor (type I), mixed cystic and solid tumor (type II), and pure solid tumor (type III). We describe a case of type III PPB that was detected in a prenatal fetus, confirmed using histopathological methods. To the best of our knowledge, this is the first case describing a type III PPB detected in a fetus. Prenatal ultrasonography is an excellent tool for detecting pulmonary lesions during the diagnostic phase, and the possibility of PPB should be considered when solid tumors are detected. Early detection can allow for the performance of full resection, leading to a better prognosis for this cancerous tumor.

Treatment and prognosis of pleuropulmonary blastoma: A single-center report of 31 cases

OBJECTIVES

Pleuropulmonary blastoma (PPB) is a very rare and highly aggressive neoplasm occurring in children, mostly under 6 years of age. We assessed the clinical characteristics, treatment modalities, treatment outcomes, and prognostic factors affecting survival in patients with PPB treated at our institution over a 10-year period to improve the prognosis.

METHODS

From November 2008 to November 2019, 31 children (21 boys and 10 girls) with a median age of 30 months (ranging, 22 days to 54 months) were treated at our institution. Here we describe the patient characteristics, treatment modalities, and treatment outcomes. The Kaplan-Meier method was used to estimate the progression-free survival (PFS) and overall survival (OS). Log-rank test was performed for comparison between groups.

RESULTS

Three children were lost to follow-up and two were dead due to postoperative complications. Of the 26 patients included in the follow-up, 16 PPB patients displayed tumor-free survival. The 5-year PFS and OS were 60.4% and 60.1% respectively. By stratified statistical analysis, the 5-year PFS and OS of type I PPB were 100%, while those of type III PPB were 43.7% and 43%, respectively. The 5-year PFS and OS of complete tumor resection were 76.5% and 75.6%, respectively, while those with tumor residue were 31.3%. The 5-year PFS and OS combined with chemotherapy were 62.2% and 61.6%, respectively, while those without chemotherapy were 0%.

CONCLUSIONS

PPB is an aggressive neoplasm. The main factors related to the prognosis of PPB are pathological type, tumor resection degree, and postoperative adjuvant therapy.

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.

Multimodality Imaging of Pleuropulmonary Blastoma: Pearls, Pitfalls, and Differential Diagnosis

Pleuropulmonary blastomas are rare, potentially aggressive embryonal cancers of the lung parenchyma and pleural surfaces that account for 0.25%-0.5% of primary pulmonary malignancies in children. Pleuropulmonary blastomas are classified as cystic (type I), mixed cystic and solid (type II), and solid (type III). Pleuropulmonary blastoma occurs in the same age group (0-6 years) as other more common solid tumors such as neuroblastoma and Wilms tumor. Differential diagnosis includes metastasis from Wilms tumor and macrocystic congenital pulmonary airway malformation (CPAM). A key pathologic and genetic discriminator is the DICER1 germline mutation found in patients with pleuropulmonary blastoma. Imaging, histopathologic, and clinical data are important to use in conjunction in order to determine the diagnosis and risk stratification of pleuropulmonary blastomas. Survival varies from poor to good, depending on type. However, the spectrum of pleuropulmonary blastoma is insufficiently understood due to the variable presentation of this rare disease. We present a current review of the literature regarding pleuropulmonary blastomas in this article.

Narrative review of congenital lung lesions

This article reviews the contemporary diagnosis and management of antenatally diagnosed congenital lung lesions. These anomalies, which include congenital pulmonary airway malformation (CPAM) (formerly congenital cystic adenomatoid malformation), bronchopulmonary sequestration (BPS), bronchogenic cyst, and congenital lobar emphysema (CLE), are relatively rare but are increasingly encountered by clinicians because of the improved resolution and enhanced sensitivity of fetal ultrasound. Serial assessment of these lesions throughout pregnancy remains the norm rather than the exception. Perinatal management strategies may differ based on initial size and growth patterns of these masses until delivery. Fetal magnetic resonance imaging and other diagnostic testing can sometimes be helpful in providing additional prognostic information. Over the last decade, maternal steroids have become standard of care in the management of larger lesions at risk for nonimmune hydrops. As a result, fetal surgical procedures, including open resection, thoracoamniotic shunting, and ex utero intrapartum treatment (EXIT), are less uncommonly performed. Decisions regarding whether delivery of these fetuses should occur in a tertiary care center with pediatric surgery coverage versus delivery at a local community hospital are now highly relevant in most prenatal counseling discussions with families. Large lung malformations may require urgent surgical removal in the early postnatal period because of respiratory distress. Other complications, such as recurrent pneumonia, pneumothorax, and cancer, are indications for postnatal lung resection on an elective basis. Many children are good candidates for minimally invasive (thoracoscopic) surgical approaches as an alternative to resection by thoracotomy. In the vast majority of cases, the overall prognosis remains excellent.

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.

Cancer Predisposition in Neonates and Infants: Recognition, Tumor Types, and Surveillance

Pediatric cancer is rare, and malignancy during the neonatal period even rarer. However, several malignancies can present in infancy, most commonly in the form of solid tumors. Specific cancer types, bilateral or multifocal disease, associated congenital malformations, and/or cancers in close relatives may herald a diagnosis of an underlying cancer predisposition syndrome. For many patients, surveillance protocols are recommended beginning at birth or during the course of maternal prenatal care. Advantages and disadvantages of genetic testing and surveillance should be discussed with families using a multidisciplinary approach, with input from a genetic counselor with expertise in pediatric cancer predisposition.

Imaging of fetal tumors and other dysplastic lesions: A review with emphasis on MR imaging

Fetal tumors and other dysplastic masses are relatively rare. They are usually the result of failure of differentiation and maturation during embryonic or fetal life; dysplastic lesions may be the consequence of an obstruction sequence. In this review, we present the most commonly encountered tumors and masses seen during fetal life. Imaging characteristics, tumoral organ of origin, and its effect on the surrounding organs and overall fetal hemodynamics are descriptors that must be relayed to the fetal surgeon and maternal fetal medicine expert, in order to institute most accurate parental counseling and appropriate perinatal treatment plan.

Fetal ultrasound and magnetic resonance imaging: a primer on how to interpret prenatal lung lesions

Fetal lung lesions include common lesions such as congenital pulmonary airway malformation (CPAM), bronchopulmonary sequestration (BPS) and combined CPAM-BPS hybrid lesions, as well as less common entities including congenital lobar emphysema/obstruction, bronchial atresia, bronchogenic cysts and rare malignant pulmonary lesions such as pleuropulmonary blastoma. Fetal lung lesions occur in approximately 1 in 15,000 live births and are thought to arise from a spectrum of abnormalities related to airway obstruction and malformation, with the lesion type depending on the timing of insult, level of bronchial tree involvement, and severity of obstruction. Lesions vary from small and asymptomatic to large and symptomatic with significant mass effect on surrounding structures. Accurate diagnosis and characterization of these anomalies is crucial for guiding patient counseling as well as perinatal and postnatal management. The goal of this review is to provide an overview of normal fetal lung appearance and imaging features of common and uncommon lesions on both ultrasound and MR imaging, and to discuss key aspects in reporting and evaluating the severity of these lesions.

Tumour predisposition and cancer syndromes as models to study gene-environment interactions

Cell division and organismal development are exquisitely orchestrated and regulated processes. The dysregulation of the molecular mechanisms underlying these processes may cause cancer, a consequence of cell-intrinsic and/or cell-extrinsic events. Cellular DNA can be damaged by spontaneous hydrolysis, reactive oxygen species, aberrant cellular metabolism or other perturbations that cause DNA damage. Moreover, several environmental factors may damage the DNA, alter cellular metabolism or affect the ability of cells to interact with their microenvironment. While some environmental factors are well established as carcinogens, there remains a large knowledge gap of others owing to the difficulty in identifying them because of the typically long interval between carcinogen exposure and cancer diagnosis. DNA damage increases in cells harbouring mutations that impair their ability to correctly repair the DNA. Tumour predisposition syndromes in which cancers arise at an accelerated rate and in different organs - the equivalent of a sensitized background - provide a unique opportunity to examine how gene-environment interactions influence cancer risk when the initiating genetic defect responsible for malignancy is known. Understanding the molecular processes that are altered by specific germline mutations, environmental exposures and related mechanisms that promote cancer will allow the design of novel and effective preventive and therapeutic strategies.

Diagnosis and treatment of pleuropulmonary blastoma in children: A single-center report of 41 cases

OBJECTIVE

This study was performed to investigate the age at onset, clinical manifestations, pathological types and features, treatment, and prognosis of pleuropulmonary blastoma (PPB) in children in an attempt to reduce the misdiagnosis rate and achieve early detection and timely intervention.

METHODS

We retrospectively studied the clinical data of 41 pediatric patients with PPB who were treated in our center from March 2002 to November 2018. The data comprised the age at onset, clinical manifestations, characteristics of familial diseases, pathological types, surgical procedures, and prognosis.

RESULTS

Twenty male and 21 female patients were included, with a 0.95:1.00 male:female ratio. In total, 51.2% of the patients were misdiagnosed as having nonneoplastic lesions at the first presentation. The interval from symptom onset to surgery/chemotherapy ranged from 5 to 210 days. The pathological types were type I (cystic) PPB (n = 5, 11.9%), for which the median age at diagnosis was 21 months (range, 8-24 months); (solid/cystic) II PPB (n = 12, 28.6%), for which the median age at diagnosis was 37 months (range, 22-112 months); and type III (solid) PPB (n = 23, 54.8%), for which the median age at diagnosis was 39 months (range, 19-156 months). The pathologic type was undefined in one patient (2.4%). The patients were mainly treated by surgery and chemotherapy. The 5-year disease-free survival rate was 69.2%.

CONCLUSION

The clinical manifestations of PPB are nonspecific, its misdiagnosis rate is high, and it has a poor prognosis. Pediatricians should be aware of the seriousness of PPB. The possibility of PPB should be considered in children with pneumothorax, multiple pulmonary cystic lesions, a family history of pulmonary cysts, a family history of PPB, or space-occupying lesions associated with DICER1 syndromes. The lesion should be closely monitored and surgically removed if necessary. The nature of the lesion should be identified early to minimize the risk of progression of the PPB to worse types because of misdiagnosis and missed diagnosis. Multidisciplinary treatment including surgery, chemotherapy, and/or radiotherapy can be applied to patients with PPB.

TYPE OF STUDY

Treatment study.

LEVEL OF EVIDENCE

Level III.

Pediatric thoracic mass lesions: Beyond the common

Thoracic mass lesions can be categorized as originating in one of the three major compartments: a) chest wall and pleura, b) lung parenchyma and airways, c) mediastinum. While some of these, such as lymphoma, are common in both children and adults, others are rare and unique to childhood. The goal of this review is to familiarize radiologists with unusual but distinctive mass lesions of the pediatric thorax.

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.

Imaging of DICER1 syndrome

DICER1 syndrome is a highly pleiotropic tumor predisposition syndrome that has been increasingly recognized in the last 10 years. Diseases in the syndrome result from mutations in both copies of the gene DICER1, a highly conserved gene that is critically implicated in micro-ribonucleic acid (miRNA) biogenesis and hence modulation of messenger RNAs. In general, susceptible individuals carry an inherited germline mutation that disables one copy of DICER1; within tumors, a very characteristic second mutation alters function of the other gene copy. About 20 hamartomatous, hyperplastic or neoplastic conditions comprise DICER1 syndrome. Most are not life-threatening, but some are aggressive malignancies. There are many unaffected carriers because penetrance is generally low; however, clinically occult thyroid nodules and lung cysts are frequent. Rare diseases of early childhood were the first recognized conditions in DICER1 syndrome, while other conditions affect adolescents and adults. The hallmarks of DICER1 syndrome are certain rare tumors including pleuropulmonary blastoma; cystic nephroma; ovarian Sertoli-Leydig cell tumor; sarcomas of the cervix, kidneys and cerebrum; pituitary blastoma; ciliary body medulloepithelioma; and nasal chondromesenchymal hamartoma. Radiologists are often the first practitioners to observe these diverse manifestations and play a primary role in recognizing DICER1 syndrome.

Asymptomatic congenital lung malformations: Is nonoperative management a viable alternative?

INTRODUCTION

The purpose of this study was to evaluate clinical outcomes in children with asymptomatic congenital lung malformations (CLM) who were initially managed nonoperatively.

METHODS

An IRB-approved retrospective review was performed on all CLMs at a single tertiary care referral center (Jan 2006-Dec 2016, n=140). Asymptomatic cases that did not undergo elective resection were evaluated for subsequent CLM-related complications based on clinical records and a telephone quality of life survey.

RESULTS

Out of 39 (27.9%) who were initially managed nonoperatively, 13 (33%) developed CLM-related symptoms and underwent surgical intervention at a median age of 6.8years (range, 0.7-19.8years). The most common indication for conversion to operative management was pneumonia (78%). Larger lesions, as measured by CT scan, were significantly associated with the need for subsequent surgical intervention (mean maximal diameter, 5.7 vs. 2.9cm; p=0.005). Based on survey data with a median follow up of 3.9years (range, 0.2-13.2years), 17% developed chronic pulmonary symptoms, including cough (11%) and asthma requiring bronchodilators (12%).

CONCLUSION

Although these data support nonoperative management as a viable alternative to surgical resection, at least one-third of CLM children eventually develop pneumonia or other pulmonary symptoms. Larger lesions are correlated with an increased risk for eventual surgical resection.

LEVEL OF EVIDENCE

Level IV.

Neonatal congenital lung tumors - the importance of mid-second-trimester ultrasound as a diagnostic clue

BACKGROUND

The differential diagnosis for primary lung masses in neonates includes a variety of developmental abnormalities; it also consists of the much rarer congenital primary lung tumors: cystic pleuropulmonary blastoma (cystic PPB), fetal lung interstitial tumor (FLIT), congenital peribronchial myofibroblastic tumor (CPMT), and congenital fibrosarcoma. Radiologic differentiation between malformations and tumors is often very challenging.

OBJECTIVE

The objective was to establish distinctive features between developmental pulmonary abnormalities and primary lung tumors.

MATERIALS AND METHODS

We conducted a retrospective study of 135 congenital lung lesions at a university mother and child center over a period of 10 years (2005-2015). During this time, we noted four tumors (two cystic PPBs and two FLITs) and 131 malformations. We recorded the following parameters: timing of conspicuity in utero (mid-second trimester, third trimester, or not seen prenatally), presence of symptoms at birth, prenatal and perinatal radiologic findings, and either histological diagnoses by pathology or follow-up imaging in non-operated cases.

RESULTS

All lesions except the four tumors were detected during mid-second-trimester ultrasound. In none of the tumors was any pulmonary abnormality found on the mid-second-trimester sonogram, contrary to the developmental pulmonary abnormalities.

CONCLUSION

The timing of conspicuity in utero appears to be a key feature for the differentiation between malformations and tumors. Lesions that were not visible at the mid-second-trimester ultrasound should be considered as tumor. A cystic lung lesion in the context of a normal mid-second-trimester ultrasound is highly suggestive of a cystic PPB. Differentiating the types of solid congenital lung tumors based upon imaging features is not yet feasible.

Long-term outcomes of congenital lung malformations

Congenital lung malformations comprise a group of anatomical abnormalities of the respiratory tree including congenital cystic malformations, bronchopulmonary sequestrations, bronchogenic cyst, bronchial atresia, and congenital lobar emphysema. These anomalies are detected with increasing frequency by pre-natal sonography, but may also present for the first time with symptoms in childhood or later life. When symptomatic, there is little controversy that resection is indicated, which is usually curative. When a lesion is asymptomatic there is greater debate regarding the benefit of resection versus continued observation. This article provides an overview of the spectrum of disorders, the management options available and the long-term outcomes associated with each treatment option.

DICER1 mutations in twelve Chinese patients with pleuropulmonary blastoma

Our aim is to examine the impact of DICER1 mutations on the pathogenesis of pleuropulmonary blastoma (PPB) by evaluating the mutation frequency and investigating the family history of Chinese patients with PPB. The family histories of 12 children with PPB recruited consecutively were surveyed. Blood samples from patients and their first-degree relatives were tested for DICER1 mutations. Whole-genome sequencing of blood samples and formalin-fixed and paraffin-embedded (FFPE) tumor tissue was performed in one family with twins. Twelve patients with PPB included six type II and six type III cases. Seven of the 12 patients harbored DICER1 mutations, six of which were frameshift or nonsense mutations. Another case carried a germline DICER1 mutation affecting the splice site. FFPE sample had a nonsense mutation in TDG and missense mutations in DICER1. In addition, two cases with DICER1 mutations were found to have lung cysts preceding the diagnosis of PPB. Furthermore, one patient had a family history remarkable for thyroid diseases. Our results indicate that the germline mutation frequency in Chinese patients with PPB is similar to the ones reported for patients from USA, UK, and Japan. Moreover, our study strongly suggests that investigating the family history and detecting germline DICER1 mutations might be of benefit to increasing awareness and improving the accuracy of the differential diagnosis of PPB from non-malignant lung cysts.

Pathomechanisms of Congenital Cystic Lung Diseases: Focus on Congenital Cystic Adenomatoid Malformation and Pleuropulmonary Blastoma

It is well established that a number of birth defects are associated with improper formation of the respiratory tract. Important progress has been made in the identification of components of the regulatory networks controlling lung morphogenesis. They comprise a variety of soluble factors, receptors, transcription factors, and miRNAs. However, the underlying molecular mechanisms remain unsolved and fundamental questions, such as those related to lung branching are still unanswered. Congenital cystic lung diseases consist of a heterogeneous group of rare lung diseases mainly detected prenatally and characterized by airway dilatation. Despite their apparent phenotypic heterogeneity, these malformations are proposed to be related to a common malformation sequence occurring during lung branching morphogenesis.

Prenatal Diagnosis and Evaluation of Sonographic Predictors for Intervention and Adverse Outcome in Congenital Pulmonary Airway Malformation

OBJECTIVE

To describe antenatal findings and evaluate prenatal risk parameters for adverse outcome or need for intervention in fetuses with congenital pulmonary airway malformation (CPAM).

METHODS

In our retrospective study all fetuses with a prenatal diagnosis of CPAM detected in our tertiary referral center between 2002 and 2013 were analyzed. Sonographic findings were noted and measurements of mass-to-thorax-ratio (MTR), congenital pulmonary airway malformation volume-ratio (CVR) and observed to expected lung-to head-ratio (o/e LHR) were conducted and correlated to fetal or neonatal morbidity and mortality and/or need for prenatal intervention.

RESULTS

67 fetuses with CPAM were included in the study. Hydropic fetuses were observed in 16.4% (11/67) of cases, prenatal intervention was undertaken in 9 cases; 7 pregnancies were terminated. The survival rate of non-hydropic fetuses with conservatively managed CPAM was 98.0% (50/51), the survival rate for hydropic fetuses with intention to treat was 42.9% (3/7). 10 (18.2%) children needed respiratory assistance. Fetuses with a CVR of <0.91 were significantly less likely to experience adverse outcome or need for prenatal intervention with sensitivity, specificity and positive/negative predictive value of 0.89, 0.71, 0.62 and 0.93, respectively. A MTR (mass-to-thorax-ratio) of < 0.51 had a positive predictive value of 0.54 and a negative predictive value of 0.96 of adverse events with a sensitivity of 0.95 and a specificity of 0.63. The negative predictive value for o/e LHR of 45% was 0.84 with sensitivity, specificity and positive predictive value of 0.73, 0.68 and 0.52, respectively.

CONCLUSIONS

The majority of cases with CPAM have a favorable outcome. MTR and CVR are able to identify fetuses at risk, the o/e LHR is less sensitive.

Pathology of asymptomatic, prenatally diagnosed cystic lung malformations

AIM

The management of asymptomatic congenital cystic lung malformations is controversial. Arguments for excision of asymptomatic lesions are the potential for infection and malignancy. Following antenatal detection, our institute performs a CT at 1month, clinic follow-up by 3months to discuss the controversial management, and offers surgery by 6months of age. We investigated the histopathology of asymptomatic lesions to determine whether there was evidence of subclinical infection or malignancy.

METHODS

A retrospective review of prospectively collected antenatal congenital cystic lung malformations more than a 10year period (2005-2014) was conducted. Information was gathered from the antenatal registry and histopathology reports. Infection was defined by the presence of microabscesses or neutrophil/macrophage infiltration, as per histopathological criteria.

MAIN RESULTS

From the cohort of 99 patients, the study focused on 69 asymptomatic lesions. These cases comprised 34 congenital pulmonary airway malformations (CPAM), 15 pulmonary sequestrations (PS), and 20 hybrid lesions. Eighteen cases (26%) had microscopic disease - 16 cases of infection and 2 tumors. The infectious cases comprised 7 with microabscesses and 9 with neutrophil/macrophage infiltration. There were two cases of tumors, namely pleuropulmonary blastoma. These tumors were followed up by the oncology team with regular imaging until 3years of age and clinical review thereafter.

CONCLUSION

Twenty-six percent of antenatally detected, asymptomatic cystic lung malformations demonstrated either subclinical infection or malignancy. This information can be used for counseling parents and determining the method of treatment.

The argument for a non-operative approach to asymptomatic lung lesions

The controversy surrounding the management of congenital lung malformations (CLMs) centre on how best to manage the increasing population of asymptomatic antenatally detected infants. Should elective surgery be offered? Or is a "watch-and-wait" policy safe? This will be addressed in this review by examining the reported complications of surgery, the risk of symptom development if lesions are left in situ and whether this may alter surgical outcomes, and importantly whether there is any long-term risk of malignancy that can be negated by surgical resection in infancy.

Pleuropulmonary Blastoma in a Neonate Diagnosed Prenatally as Congenital Pulmonary Airway Malformation

Pleuropulmonary blastoma is an extremely rare lung neoplasm exclusive to children under 5 years of age. It presents a diagnostic challenge both prenatally and in early childhood due to its similarity to benign lung cysts, which are managed differently. We present the first case, to our knowledge, of a neonate with pleuropulmonary blastoma and myelomeningocele, though prenatally diagnosed as a congenital pulmonary airway malformation. We detail the prenatal imaging that facilitated counseling and delivery management in addition to the correlating postnatal imaging.

Antenatally diagnosed lung malformations: a plea for long-term outcome studies

There is a wide variation in the management of infants with antenatally diagnosed lung malformations, with many paediatric surgeons and respiratory paediatricians recommending early investigations for all infants and a surgical excision for the majority of lesions, while others favour a conservative management for all asymptomatic infants. The benefits and risks of a surgical intervention have to be compared with the natural history of the untreated malformation and cohort studies from foetal diagnosis to adult life are required to provide the relevant evidence. Careful and repeated surveillance of identified foetuses is essential as recent advances in foetal medicine and surgery have improved the outcomes for the small minority, who are at risk of developing hydrops.

Pleuropulmonary Blastoma: Evolution of an Entity as an Entry into a Familial Tumor Predisposition Syndrome

Pleuropulmonary blastoma (PPB) is the most common primary malignant neoplasm of the lung in children. Like other solid dysontogenic neoplasms, this tumor typically presents before 7 years of age. The earliest manifestation is the presence of a lung cyst(s), which is usually recognized in the first year of life and is difficult to differentiate on the basis of imaging studies from non-neoplastic cysts of early childhood. From a multilocular cyst, PPB has the potential to progress to a high-grade multipatterned primitive sarcoma. More than 65% of all affected children have a heterozygous germline mutation in DICER1. The DICER1 PPB familial tumor predisposition syndrome is initially recognized in most cases on the basis of PPB alone but also by several other unique and characteristic extrapulmonary tumors, including pediatric cystic nephroma, nasal chondromesenchymal hamartoma, nodular lesions of the thyroid, embryonal rhabdomyosarcoma of the cervix, and ciliary body medulloepithelioma.

DICER1: mutations, microRNAs and mechanisms

Dicer is central to microRNA-mediated silencing and several other RNA interference phenomena that are profoundly embedded in cancer gene networks. Most recently, both germline and somatic mutations in DICER1 have been identified in diverse types of cancer. Although some of the mutations clearly reduce the dosage of this key enzyme, others dictate surprisingly specific changes in select classes of small RNAs. This Review reflects on the molecular properties of the Dicer enzymes in small RNA silencing pathways, and rationalizes the newly discovered mutations on the basis of the activities and functions of its determinants.

Cystic lung lesions in newborns and young children: differential considerations and imaging

Numerous diverse entities produce cystic lung changes in neonates and young children. This review provides an evidence-based, age-appropriate, differential diagnostic framework to use when confronted with pulmonary cystic changes. The categories of diseases that have been discussed include congenital cystic bronchopulmonary malformations, neoplastic conditions, infections, collagen or soft tissue abnormalities, and mimics of cystic lung disease. An understanding of the pathophysiology, imaging appearance, and demographics of these entities is essential in guiding optimal care. Important educational points include differentiating bronchopulmonary malformations from neoplasms and the management and surveillance of lung cysts in young children.

Conservative management of antenatally diagnosed cystic lung malformations

AIM

To review the outcome of all antenatally diagnosed conservatively managed congenital lung malformations (CLMs) managed at our centre.

METHODS

All patients diagnosed antenatally with cystic lung malformations from 2001 to 2011, at a tertiary referral paediatric surgical centre practising a policy of conservative management of asymptomatic cases, were retrospectively reviewed. Data were collected from medical case notes and radiology reports. Ethical approval was obtained from our institutional research and development department.

RESULTS

The complete records of 74 fetuses antenatally diagnosed with CLM were reviewed. There were 72 live births, at a median gestation of 39.6 weeks. Emergency lobectomy was performed in one symptomatic neonate. Elective lobectomies were performed at parental request in three asymptomatic infants, one of whom had a family history of synovial sarcoma. Two patients developed pneumonia in the affected lobe during early childhood and proceeded to lobectomy at the age of 3 years. One patient with a bronchopulmonary sequestration required embolisation for cyanotic episodes. The remaining 65 patients have been conservatively managed to date, and none have required hospital admission. Less than a quarter report mild respiratory symptoms such as cough or wheeze. Median follow-up is 5 years.

CONCLUSIONS

This retrospective cohort study of 74 consecutive CLMs diagnosed antenatally over a 10-year period demonstrates that most of these lesions will remain asymptomatic throughout childhood. Although the natural history of CLMs in later years remains to be elucidated, we hope that this report on medium-term outcomes will be useful to clinicians who undertake antenatal counselling and may inform the discussion on how best to manage these children.

Thoracoscopic lobectomy for type I pleuropulmonary blastoma in an infant

Pleuropulmonary blastoma (PPB) is a rare, aggressive, intrathoracic mesenchymal neoplasm associated with cystic lung lesions. The authors describe an 8-month-old male who underwent thoracoscopic left upper lobectomy for a cystic lung lesion initially diagnosed as congenital pulmonary airway malformation. Pathology revealed type I PPB.

Clinicopathological and extensive immunohistochemical study of a type II pleuropulmonary blastoma

Pleuropulmonary blastoma (PPB) is a rare malignant dysontogenetic neoplasm primarily affecting younger children, even in newborns with an unfavorable outcome. PPB is histologically composed of a primitive, variably mixed blastematous and sarcomatous components, and exclusively subclassified as type I (purely cystic), type II (both cystic and solid elements) and type III (completely solid) by increasing histological evidence of malignancy. At present, well-documented cases or cases of truly precise presentation of either pathological or immunohistochemical findings in PPB are rare. The authors report one case of PPB in a 44-month-old child presenting as a solid and cystic mass with special emphasis on its radiological, histopathological and immunohistochemical aspects. The histological diagnosis was PPB, which would belong to the type II category.

EXIT-to-resection for fetuses with large lung masses and persistent mediastinal compression near birth

PURPOSE

To identify prenatal diagnostic features that will help select fetuses with lung masses (LM) who may benefit from ex-utero intrapartum treatment (EXIT procedure) as the preferred mode of delivery.

METHODS

The CCAM-volume ratio (CVR), fetal treatment, and outcomes of all fetuses with LM evaluated between 2001 and 2011 were reviewed retrospectively. Fetuses with hydrops or CVR>1.6 were classified as high risk. Indications for fetal interventions included hydrops and heart failure, and indication for EXIT-to-resection was the finding of persistent mediastinal compression (PMC) near birth.

RESULTS

Of 110 fetuses evaluated for LM, 78 were classified as low-risk. No fetus in this group had PMC near birth and none required perinatal treatment. Of 32 high-risk fetuses, 8 developed heart failure of which 4 survived (3 following fetal surgery). Nine high-risk fetuses with no PMC near birth were asymptomatic postnatally and treated electively. Sixteen high-risk fetuses had PMC near birth. All 9 babies with PMC treated with EXIT-to-resection did well with discharge at a median of 10 days post-operatively. All 7 fetuses treated without an EXIT developed respiratory distress following birth requiring an urgent operation; 2 died.

CONCLUSION

The EXIT-to-resection procedure is a favorable delivery approach for those fetuses with large LM and PMC near birth.

Evaluation of the prenatally diagnosed mass

With the advent of advanced imaging technologies, the field of prenatal diagnosis and counseling has grown rapidly. The use of fetal ultrasound and ultrafast magnetic resonance imaging has allowed for prenatal identification of structural anomalies as well as neoplasm. The differential diagnosis of a fetal mass is dependent upon its location and the tissue characteristics of the mass on imaging. The use of amniocentesis for chromosomal analysis and genetic testing for known tumor-related genetic abnormalities may aid in further refining the diagnosis. Herein we describe a general diagnostic algorithm for fetal masses based upon their location within the body and how the appropriate diagnostic modalities may be applied in the clinical setting.

Pleuropulmonary blastoma: a single-institution experience

Pleuropulmonary blastoma (PPB) is a rare primary intrathoracic mesenchymal malignancy that occurs exclusively in early childhood. Twelve patients were diagnosed with PPB (1 type I, 5 type II, and 6 type III) between 1979 and 2009 at our institution. Upfront complete tumor resection was successful in 5 of 6 patients. Six patients had biopsy followed by neoadjuvant chemotherapy, 2 had complete tumor resection, and 2 had microscopic residual disease after surgery. All patients received vincristine, dactinomycin, and cyclophosphamide chemotherapy. Eight received additional chemotherapy with doxorubicin, cisplatin, etoposide, or ifosfamide. Three patients received local irradiation. The 5-year event-free and overall survivals were 33% ± 14% and 42% ± 14%, respectively. Median time to progression was 8 months. Five of 9 patients with gross total resection survived, whereas all 3 with gross residual disease died. Three of 5 survivors did not receive radiation. A high index of suspicion for PPB must be maintained in all patients diagnosed with intrathoracic sarcoma in early childhood. Gross total resection is necessary for cure, and selected patients do not require radiation therapy.

[Congenital malformations of the lung, the radiologist's point of view]

Congenital lung malformations include a complex range of developmental abnormalities. Currently, most are diagnosed prenatally or during early childhood. They may, however, be discovered later, incidentally or in connection with non-specific symptoms, sometimes severe. Knowledge of their radiological appearances is necessary for their detection. Proper technique and analysis of cross-sectional imaging, computed tomography and magnetic resonance imaging, allow a definitive diagnosis in most patients and pre-treatment evaluation of surgical cases. This review will describe the radiological aspects of congenital pulmonary malformations, especially those which may occur in late childhood or adult life. When present, alternative diagnoses will be discussed. A distinction will be made between anomalies originating from bronchopulmonary structures, such as bronchial atresia, bronchogenic cyst, congenital lobar overinflation, cystic adenomatoid malformation, and forms related to vascular anomalies (vascular rings, anomalous left pulmonary artery, pulmonary underdevelopment, proximal interruption of the pulmonary artery, pulmonary sequestration, scimitar syndrome).

Congenital lung lesions

Confusion, controversy, and uncertainty are all terms applicable to the diagnosis and management of congenital lung lesions both prenatally and postnatally. This review examines the current status of fetal diagnosis and treatment of these lesions; reviews the various classifications, including congenital cystic adenomatoid malformation/congenital pulmonary airway malformation, sequestrations, variants and hybrid lesions; discusses the risk of malignant transformation or misdiagnosis with pleuropulmonary blastoma; presents the arguments in favor and against resection of asymptomatic lesions, the timing of such resection, and the long-term pulmonary function after resection; and reviews the experience with thoracoscopic resection of congenital lung lesions.

Long term respiratory outcomes of congenital thoracic malformations

The advent of universal antenatal ultrasonography in many countries has revealed the full spectrum of congenital thoracic malformations (CTMs) and presented clinicians with a number of practical dilemmas to do with diagnosis and management. We present a review of the most common forms of CTMs, including congenital cystic adenomatoid malformation, bronchopulmonary sequestration, and lobar and segmental emphysema.

Fetal lung interstitial tumor: a cause of late gestation fetal hydrops

Most fetal lung masses present by mid gestation, grow during the canalicular phase of lung development (18-26 weeks of gestation), and plateau in growth or shrink after 26 weeks of gestation. We describe the unique case of a fetal lung mass presenting at 37 weeks of gestation with hydrops and fetal heart failure. The late growth of this lesion and resultant hydrops prompted resection as part of the ex utero intrapartum treatment. Histopathology revealed a rare, recently described fetal lung interstitial tumor. This case demonstrates that a subset of fetal lung masses may continue to grow later in gestation and emphasizes the need for late gestation imaging and close follow-up in this patient cohort.

Impact of prenatal diagnosis and therapy on neonatal surgery

The field of neonatal surgery is now inextricably linked to the field of obstetrics. Neonatologists and surgical specialists experienced with the postnatal management and outcomes of infants with various disorders now look in utero along with obstetricians and fetal medicine specialists to characterize the development and well-being of fetuses with congenital anomalies with a goal to optimize fetal, perinatal and postnatal management. The purpose of this article is to examine how prenatal diagnosis and therapy has influenced neonatal surgery. An overview of prenatal diagnosis and the evolution of fetal therapy are provided. In addition, we review the impact of prenatal diagnosis and therapy on the management and outcomes of infants with specific anomalies, including congenital lung malformations, sacrococcygeal teratoma, myelomeningocele, giant fetal neck masses, diaphragmatic hernia and congenital heart defects.

Radical resection of pleuropulmonary blastoma

Pleuropulmonary blastoma (PPB) is a rare intrathoracic neoplasm of early childhood that occurs in the lung or visceral pleura. We present a case of a 5-year-old boy with a cough, left-sided chest pain and progressive dyspnea on exertion. The patient had had an operation for a congenital lung cyst of the left lower lobe, six months prior to the present admission. A CT showed a heterogeneously enhancing mass lesion filling the left hemithorax. CT-guided fine needle aspiration cytology of the mass was inconclusive. En bloc resection of the mass along with left lower lobe, the involved ribs and left diaphragm was performed. The diaphragmatic defect was repaired using prolene mesh. Histopathology of the resected specimen showed solid and cystic areas consistent with type II PPB. The patient received adjuvent chemotherapy and was doing well 23 months after surgery. Radical resection of the tumor followed by adjuvent chemotherapy provides the only hope of salvaging cases of type II or type III PPB.

Prenatal diagnosis and outcome of fetal lung masses

AIM

The purpose of this study is to evaluate the accuracy of prenatal diagnostic features, particularly congenital cystic adenomatoid malformation volume ratio (CVR), in predicting outcomes for fetuses with lung masses.

METHODS

The records and imaging features of all fetuses referred to the Texas Children's Fetal Center with a fetal lung mass between July 2001 and May 2010 were reviewed retrospectively. Data collected included gestational age (GA) at diagnosis, fetal magnetic resonance imaging findings, CVR, mass size, nature of fetal treatment, surgical findings, pathology, and outcome. Data were analyzed for predicting development of hydrops or the need for fetal therapy using receiver operating characteristic curves.

RESULTS

Of 82 fetuses (41 male) evaluated for a lung mass, 53 (65%) were left-sided (1 bilateral), and the mean (SD) GA at diagnosis was 21.5 (4.3) weeks. Seventy-three fetuses underwent fetal magnetic resonance imaging at a mean (SD) GA of 26.1 (4.6) weeks. Thirteen fetuses (16%) had fetal treatment. Four fetuses with hydrops underwent open fetal surgical resection, and 3 survived. Six fetuses with large lung masses and persistent mediastinal compression near term underwent ex-utero intrapartum therapy-to-resection procedures, and 3 fetuses with hydrops underwent serial thoracentesis. Congenital cystic adenomatoid malformation volume ratio correlated strongly with the development of hydrops and the need for fetal therapy with an area under the receiver operating characteristic curve of 0.96 (P < .0001) and 0.88 (P < .0001), respectively. Of 18 fetuses with a CVR greater than 2.0 compared with 2 (3%) of 60 with a CVR of 2.0 or less, 10 (56%) required fetal intervention (P < .0001).

CONCLUSION

Congenital cystic adenomatoid malformation volume ratio correlates strongly with the development of fetal hydrops and the need for fetal intervention. A threshold value of 2.0 yields the most powerful statistical results.

[Child pleuropulmonary blastoma]

Pleuropulmonary blastoma is an extremely rare and aggressive thoracic tumour seen exclusively in children. The initial symptoms are respiratory and non specific and the chest X-ray done in that context reveals a thoracic mass. The chest CT scan then leads to the diagnosis of a cystic, mixt or solid mass. The diagnosis will be affirmed on anatomopathology of the tumour or biopsy. There are three different histological types: type I, cystic, type II, cystic and solid and type III, solid exclusively. Type I is less aggressive and its treatment is essentially surgical. Types II and III are highly aggressive and require surgery associated to polychemotherapy. In all cases, surgery is essential and should be the most complete possible. Extension and follow-up exams will include bone scan and brain imagery searching for metastasis as well as abdominal ultrasound searching associated renal lesions because 30% of pleuropulmonary blastoma are part of a familial predisposition syndrome.

[Pleuropulmonary blastoma: a clinicopathological analysis]

背景与目的

胸膜肺母细胞瘤是一种罕见的且有其独特临床病理特征的恶性肿瘤，本文旨在探讨胸膜肺母细胞瘤的临床病理学特点及鉴别诊断等。

方法

收集5例胸膜肺母细胞瘤，复习患者临床资料，进行组织学及免疫组化观察，并结合文献复习分析。

结果

5例胸膜肺母细胞瘤患者年龄为21个月-47个月，平均为32.8个月；肿瘤主要位于胸腔，4例伴有胸腔积液。组织学观察：Ⅰ型胸膜肺母细胞瘤1例，呈单纯囊性；Ⅱ型胸膜肺母细胞瘤2例，呈囊实性，实性区伴横纹肌分化及灶性软骨样结节；Ⅲ型胸膜肺母细胞瘤2例，完全呈实性，可见间变性未分化肉瘤样成分。免疫组化染色显示肿瘤细胞呈Vimentin（+），部分肿瘤细胞呈Desmin和Myogenin（+），软骨样结节呈S-100（+）；PCK、EMA、CD99等均（-）。

结论

胸膜肺母细胞瘤是一种罕见的主要发生于婴幼儿肺和胸膜的高侵袭性恶性肿瘤，各亚型均有其临床病理学特点。诊断方面应与肺先天性囊性腺瘤样畸形、胚胎性横纹肌肉瘤等良恶性病变鉴别。