Discriminating preoperative features of pleuropulmonary blastomas (PPB) from congenital cystic adenomatoid malformations (CCAM): a retrospective, age-matched study

[Congenital pulmonary malformations : Diagnosis and treatment]

PERFORMANCE

Congenital pulmonary malformations (CPM) are rare and can be associated with high morbidity. Clinical presentation, diagnostic procedures, imaging, and therapy of CPM are discussed.

ACHIEVEMENTS

Today, most CPM can be diagnosed prenatally by ultrasound. Postnatally, respiratory symptoms up to respiratory failure and recurrent lower respiratory tract infection are typical findings. Due to low diagnostic accuracy of chest x‑ray in CPM, all children with prenatal diagnosis of CPM or postnatally suspected CPM should undergo cross-sectional imaging.

PRACTICAL RECOMMENDATIONS

Based on imaging alone, the various subtypes of CPM cannot be definitively differentiated, which is why histological confirmation remains the gold standard. Surgical resection is the standard of care with minimally invasive procedures increasingly being employed. In certain situations, a watch-and-wait approach is possible.

Prevalence of lung cysts in adolescents and adults with a germline DICER1 pathogenic/likely pathogenic variant: a report from the National Institutes of Health and International Pleuropulmonary Blastoma/DICER1 Registry

BACKGROUND

Pleuropulmonary blastoma (PPB), the hallmark tumour associated with DICER1-related tumour predisposition, is characterised by an age-related progression from a cystic lesion (type I) to a high-grade sarcoma with mixed cystic and solid features (type II) or purely solid lesion (type III). Not all cystic PPBs progress; type Ir (regressed), hypothesised to represent regressed or non-progressed type I PPB, is an air-filled, cystic lesion lacking a primitive sarcomatous component. This study aims to evaluate the prevalence of non-progressed lung cysts detected by CT scan in adolescents and adults with germline DICER1 pathogenic/likely pathogenic (P/LP) variants.

METHODS

Individuals were enrolled in the National Cancer Institute Natural History of DICER1 Syndrome study, the International PPB/DICER1 Registry and/or the International Ovarian and Testicular Stromal Tumor Registry. Individuals with a germline DICER1 P/LP variant with first chest CT at 12 years of age or older were selected for this analysis.

RESULTS

In the combined databases, 110 individuals with a germline DICER1 P/LP variant who underwent first chest CT at or after the age of 12 were identified. Cystic lung lesions were identified in 38% (42/110) with a total of 72 cystic lesions detected. No demographic differences were noted between those with lung cysts and those without lung cysts. Five cysts were resected with four centrally reviewed as type Ir PPB.

CONCLUSION

Lung cysts are common in adolescents and adults with germline DICER1 variation. Further study is needed to understand the mechanism of non-progression or regression of lung cysts in childhood to guide judicious intervention.

COllaborative Neonatal Network for the first European CPAM Trial (CONNECT): a study protocol for a randomised controlled trial

INTRODUCTION

Consensus is lacking on the optimal management of asymptomatic congenital pulmonary airway malformation (CPAM). For future studies, the CONNECT consortium (the COllaborative Neonatal Network for the first European CPAM Trial)-an international collaboration of specialised caregivers-has established consensus on a core outcome set of outcome parameters concerning respiratory insufficiency, surgical complications, mass effect and multifocal disease. These outcome parameters have been incorporated in the CONNECT trial, a randomised controlled trial which, in order to develop evidence-based practice, aims to compare conservative and surgical management of patients with an asymptomatic CPAM.

METHODS AND ANALYSIS

Children are eligible for inclusion after the CPAM diagnosis has been confirmed on postnatal chest CT scan and they remain asymptomatic. On inclusion, children are randomised to receive either conservative or surgical management. Subsequently, children in both groups are enrolled into a standardised, 5-year follow-up programme with three visits, including a repeat chest CT scan at 2.5 years and a standardised exercise tolerance test at 5 years.The primary outcome is exercise tolerance at age 5 years, measured according to the Bruce treadmill protocol. Secondary outcome measures are molecular genetic diagnostics, validated questionnaires-on parental anxiety, quality of life and healthcare consumption-, repeated imaging and pulmonary morbidity during follow-up, as well as surgical complications and histopathology. This trial aims to end the continuous debate surrounding the optimal management of asymptomatic CPAM.

ETHICS AND DISSEMINATION

This study is being conducted in accordance with the Declaration of Helsinki. The Medical Ethics Review Board of Erasmus University Medical Centre Rotterdam, The Netherlands, has approved this protocol (MEC-2022-0441). Results will be disseminated through peer-reviewed scientific journals and conference presentations.

TRIAL REGISTRATION NUMBER

NCT05701514.

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.

Surgical Management of Congenital Lung Malformations

Congenital lung malformations (CLMs) are commonly diagnosed prenatal lesions with varied natural history. Prenatal diagnosis and monitoring help to guide fetal interventions, delivery planning, and need for urgent perinatal surgical interventions. All prenatally diagnosed CLMs should be evaluated postnatally, typically with cross-sectional imaging, because many lesions persist despite the appearance of complete 'regression' in utero. Management of CLMs in asymptomatic infants weighs the surgical and anesthetic risk of prophylactic resection against the risk of expectant management, including the possibility of infection, malignant degeneration, and more complicated surgical resection later with loss of compensatory lung growth.

Hypertensive pneumothorax with cystic lesions: Pleuropulmonary blastoma in an infant

Pleuropulmonary blastoma (PPB) is a rare primitive malignant lung cancer that occurs in pediatric age. Its main differential diagnosis is congenital cystic pulmonary malformation (CPAM). A 30-day-old infant with respiratory failure obtained a chest x-ray and a computed tomography scan (CT) which revealed hypertensive pneumothorax with multifocal bilateral cysts. After thoracic drainage, the patient underwent multiple thoracoscopic pulmonary resections. The first histological diagnosis was of type 2 CPAM. During the radiological follow-up, an increase in the number and dimension of the lesions was detected. Thus, a histological revision was performed, leading to the diagnosis of type I PPB, at nine months. The patient subsequently underwent chemotherapy. At the five-year follow-up appointment, chest magnetic resonance (MR) and CT scans showed a dimensional increase in size of the lesions, with the risk of recurrent pneumothorax. An upper right lobectomy and wedge resection of the residual cysts were performed. Control MR scans showed normalization of the lung parenchyma and the patient showed substantial clinical improvement.

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.

Quantitative CT imaging analysis to predict pathology features in patients with a congenital pulmonary airway malformation

BACKGROUND

Risk for infection and potential malignant degeneration are the most common arguments for resecting asymptomatic Congenital Pulmonary Airway Malformations (CPAM). We aimed to investigate if CT- imaging characteristics can be used to predict histopathological features, by using an objective quantitative CT scoring method.

METHODS

Archival CPAM tissue samples were histologically re-assessed and patients who had a pre-operative volumetric CT-scan were included. Lung disease was quantified using the newly-developed congenital lung abnormality quantification(CLAQ) scoring method and obtained percentages were used to predict histopathological signs of inflammation and presence of mucinous proliferation (MP). Because MP is presumed a precursor for mucinous adenocarcinoma in situ (AIS) this method was also used to compare CT-scans of patients with AIS to those with only CPAM.

RESULTS

Thirty-three CPAM patients were included of which 13(39%) had histological signs of inflammation and 8(24%) had a MP. Patients with inflammation had a significantly smaller lesion (14% vs 38%) while those with MP had more extensive disease (54%vs17%). Patients with AIS had a significantly smaller lesion compared to CPAM patients (5%vs29%). Significant predictors for inflammation were smaller lesion size and percentage hypodensity within lesions while a larger lesion size and percentage parenchymal hyperdensity (solid lung tissue components) were predictors for MP as well as AIS.

CONCLUSIONS

Smaller CPAM lesions may be more susceptible to inflammation while larger lesions may be associated with the presence of MP. Parenchymal hyperdensity is found as a predictor for MP as well as AIS and should therefore elicit more extensive gross sampling.

LEVEL OF EVIDENCE

Level III.

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.

Thoracoscopic surgery for congenital lung malformations: Does previous infection really matter?

BACKGROUND/ PURPOSE

Elective resection of congenital lung malformations (CLMs) is still debatable. The two main risks are malignant transformation and recurrent pulmonary infections. Our study aimed to assess the effect of previous pulmonary infection on the intraoperative and postoperative courses of thoracoscopic surgery for CLMs.

METHODS

This is a retrospective study including all thoracoscopic lung resections for CLMs between 2010 and 2019. Ninety patients were included. There was a history of previous pulmonary infection in 28 patients (group A) and no such history in 62 patients (group B).

RESULTS

The median age at operation for group A was 20.4 months (IQR:14.9-41.4) versus 15.1 months (IQR:9.7-20.8) in group B (p = 0.006). There were 10 conversions (35.7%) in group A and 8 (12.9%) in group B (p = 0.02). The operative time was significantly shorter in group B (p<0.002). In group A, 32.1% of patients experienced postoperative fever versus 11.3% of group B (p = 0.03), with higher antibiotics requirement (28.6% versus 6.5% respectively, p = 0.007). However, no significant differences were found in terms of postoperative complications (p = 0.99).

CONCLUSION

Earlier intervention for CLMs before the development of pulmonary infection carries higher chances for the success of the thoracoscopic approach with shorter operative time and more uneventful postoperative courses.

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.

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.

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.

Pleuropulmonary blastoma: a report from the TREP (Tumori Rari in Età Pediatrica) Project

INTRODUCTION

Pleuropulmonary blastoma (PPB) is a rare, aggressive mesenchymal tumor of childhood. The Italian Tumori Rari in Età Pediatrica (TREP) Registry was the first in Europe dedicated to prospective data collection on rare pediatric tumors. We analyzed data from an Italian series of patients with PPB, focusing on the role of the TREP Project.

METHODS

We considered patients aged 0-14 with histologically confirmed diagnosis, registered in population-based cancer registries (before 2000) or the TREP Registry (2000 to 2014), and analyzed data on clinical characteristics, treatment, and outcome. Event-free survival (EFS) and overall survival (OS) were estimated. Relevant prognostic factors were identified performing a univariate analysis.

RESULTS

Thirty-seven cases were included (7 type I, 13 type II, 17 type III). The average diagnosis rate rose from 1.10 to 1.73 cases/year after the TREP Project started. All patients underwent surgery, 33 received chemotherapy, and 9 had radiotherapy. The median follow-up was 8.7 years. For type I, II, and III, respectively, the 5-year OS was 85.7% (33.4-97.9), 52.7% (23.4-75.5), and 57.8% (31.1-77.3); the 5-year EFS was 85.7% (33.4-97.9), 52.7% (23.4-75.5), and 52.9% (27.6-73.0). Favorable prognostic factors for EFS were Intergroup Rhabdomyosarcoma Study (IRS) stage I (p = 0.03) and T1 tumor (p = 0.05). A total of 78.3% of patients who had chemotherapy after 2000 received a standardized treatment.

CONCLUSIONS

The TREP Registry showed an excellent capacity for registering cases of PPB. Patients received homogeneous treatment after the TREP Project started. Long-term outcomes were excellent for type I and unsatisfactory for type II and III. Tumor invasiveness and IRS stage were of prognostic value.

Symptom development in originally asymptomatic CPAM diagnosed prenatally: a systematic review

PURPOSE

For the approximately three quarters of patients with a prenatal diagnosis of congenital pulmonary airway malformation (CPAM) who are asymptomatic at birth, the chance of eventually developing symptoms is unknown. We sought to explore the natural history of asymptomatic CPAM.

METHODS

We searched EMBASE, MEDLINE, and the first 50 results from Google Scholar. Studies describing the natural history of prenatally diagnosed, initially asymptomatic CPAM were included. For asymptomatic patients initially managed non-surgically, we tabulated the proportion who went on to develop symptoms as well as the median age at symptom development.

RESULTS

We included data from 19 retrospective studies on 353 patients. Of the 128 patients managed expectantly, 31 (24.2%) developed symptoms requiring surgical intervention. The median age at symptom development was 7.5 months (range 15 days-5 years).

CONCLUSION

The risk for developing respiratory symptoms exists with originally asymptomatic CPAM patients, but the exact risk is difficult to predict. Parents may be given the value of approximately 1 in 4 as an estimate of the proportion of asymptomatic CPAM patients who go on to develop symptoms, which will help them make an informed decision regarding the option of elective surgery.

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.

Pediatric imaging in DICER1 syndrome

BACKGROUND

DICER1 syndrome, arising from a mutation in the DICER1 gene mapped to chromosome 14q32, is associated with an increased risk of a range of benign and malignant neoplasms.

OBJECTIVE

To determine the spectrum of abnormalities and imaging characteristics in patients with DICER1 syndrome at a tertiary pediatric hospital.

MATERIALS AND METHODS

This retrospective analysis evaluated imaging in patients ≤18 years with DICER1 germline variants between January 2004 and July 2016. An imaging database search including keywords pleuropulmonary blastoma, cystic nephroma, pineoblastoma, embryonal rhabdomyosarcoma, ovarian sex cord-stromal tumor, ovarian Sertoli-Leydig cell tumor and DICER1 syndrome, was cross-referenced against the institutional Cancer Genetics Program database, excluding patients with negative/unknown DICER1 gene testing.

RESULTS

Sixteen patients were included (12 females; mean age at presentation: 4.2 years, range: 14 days to 17 years), with surveillance imaging encompassing the following modalities: chest X-ray and CT; abdominal, pelvic and neck US; and brain and whole-body MRI. Malignant lesions (68.8% of patients) included pleuropulmonary blastoma (5), pineoblastoma (3), ovarian Sertoli-Leydig cell tumor (1), embryonal rhabdomyosarcoma (1) and renal sarcoma (1); benign lesions (37.5% of patients) included thyroid cysts (2), thyroid nodules (2), cystic nephroma (2), renal cysts (1) and pineal cyst (1). A common lesional appearance observed across modalities and organs was defined as the "cracked windshield" sign.

CONCLUSION

The spectrum of DICER1-related tumors and the young age at presentation suggest early surveillance of at-risk patients is critical, while minimizing exposure to ionizing radiation.

Type III pleuropulmonary blastoma in a dicer1 germline mutation carrier: The management of residual lung cystic lesions

Pleuropulmonary blastoma (PPB) is a rare malignancy of childhood. It often represents a manifestation of a hereditary tumor predisposition syndrome (DICER1 syndrome). Because of its malignant potential, surgical resection of cystic lung lesions is recommended in germline DICER1 mutation carriers. We present a case of a 3-year-old male child with type III PPB successfully managed with ifosfamide, vincristine, actinomycin-D, and doxorubicin (IVADo) chemotherapy and surgery. A heterozygous germline pR688X mutation of DICER1 gene was demonstrated. Six years after primary diagnosis, several small lung cysts remained stable without further therapy. The management of residual asymptomatic lung cysts represents a clinical challenge in these patients.

It's Rare So Be Aware: Pleuropulmonary Blastoma Mimicking Congenital Pulmonary Airway Malformation

Pleuropulmonary blastoma (PPB) is a rare aggressive malignant tumor of infancy and early childhood. The tumor arises in the lung and pleura and is regarded as a pulmonary dysontogenetic or embryonic neoplasm. Four types are defined in literature. Type I PPB is a rare, cystic lung neoplasm in infants characterized by subtle malignant changes and a good prognosis. Recurrences after type I PPB are usually advanced with a poor prognosis.

We report this case to increase awareness about this entity so that the pediatricians, pediatric surgeons, radiologist, and pathologist recognize it early.

Morbidity after elective resection of prenatally diagnosed asymptomatic congenital pulmonary airway malformations

BACKGROUND/AIM

The optimal management of prenatally diagnosed asymptomatic congenital pulmonary airway malformations (CPAM) is controversial. Since there is a paucity of data relating to surgical risks in this specific population, we reviewed our experience to further inform this controversy.

METHODS

Ethically approved 10 year (2004-2013) retrospective review. Patients were included only if the CPAM was diagnosed prenatally and remained asymptomatic. Indication for surgery was physician recommendation and/or parental choice.

MAIN RESULTS

Sixty patients were identified. Median age at surgery was 6.5 months (range 65 days to 9.6 years). Resections were performed thoracoscopically (n = 51, one conversion) or by thoracotomy (n = 9). Surgical time was 2.5 hr (43 min to 4.75 hr). A chest drain was used in 58/60 and remained in situ 53 hr (23-108). There were no intra-operative complications or blood transfusions. All patients were extubated at the end of the procedure with no re-intubations. Post-operative hospitalization was 73.4 hr (23.8 hr to 4.2 days). Overall, complications occurred in 14/60 (23%). Eleven were minor but three were major: tension pneumothorax associated with new presentation of a small previously undiagnosed diaphragmatic hernia 5 days following resection; aggressive fibromatosis of the chest wall in the region close to resection 2 years later; and near-fatal hypovolemic cardiac arrest due to massive haemorrhage from a feeding vessel on postoperative day 7. There were no deaths and no cases of pleuropulmonary blastoma.

CONCLUSION

Resection of prenatally diagnosed asymptomatic CPAM is associated with a significant risk of complications, which may be life threatening. These data contribute to a balanced discussion of risks and benefits for these children.

Magnetic resonance imaging of the mediastinum, chest wall and pleura in children

The acceptance of applications for the use of chest MRI in children has been somewhat slow and selective. The use of MRI to image chest wall lesions is likely the most common and widely used indication, aside from the widespread and somewhat sophisticated use of MRI in imaging the cardiovascular structures of the chest. In this respect, fairly standard variations of T1-W, T2-W and contrast-enhanced imaging can be used, similar to the sequences used for musculoskeletal lesions elsewhere in the body. Imaging of the anterior mediastinal masses should be performed in conjunction with a detailed pre-test clinical examination to determine potential cardiovascular compromise. MRI in the setting of middle mediastinal adenopathy, congenital mediastinal cysts or posterior mediastinal masses, however, has been shown to be more effective and more comprehensive than multidetector CT. Although sonographic imaging is the initial modality of choice for pleural abnormalities, MR imaging is extremely effective and clinically useful in the setting of a potentially ambiguous sonographic examination. Faster imaging protocols are likely to increase the acceptance of MRI to replace multidetector CT for many pediatric chest lesions.

Surgical versus conservative management of congenital pulmonary airway malformation in children: A systematic review and meta-analysis

BACKGROUND

The ideal management of infants born with asymptomatic congenital pulmonary airway malformation (CPAM) is controversial. We performed a systematic review and meta-analysis comparing elective resection versus expectant management.

METHODS

We searched CENTRAL, MEDLINE, EMBASE, CINAHL, and PubMed for studies describing the management of asymptomatic CPAM and reporting on postoperative morbidity, mortality, and length of hospital stay (LOS). We performed meta-analyses when possible and provide a narrative summary of results.

RESULTS

One nonrandomized prospective and eight retrospective studies met our inclusion criteria. Out of 168 patients, 70 underwent surgery before symptoms developed with seven experiencing postoperative complications (10.0%); 63 developed symptoms while being managed expectantly and subsequently underwent surgery with 20 complications (31.8%). Thirty-five patients continued to be followed nonsurgically (three months to nine years of follow-up). Morbidity was higher with surgery after symptom development (6 studies; odds ratio 4.59, 95% confidence interval (CI) 1.40 to 15.11, P<0.01); there was no difference in LOS (3 studies; mean difference 4.96, 95% CI -1.75 to 11.67, P=0.15). There were no related deaths.

CONCLUSIONS

Elective resection of asymptomatic CPAM lesions is safe and prevents the risk of symptom development, which may result in a more complicated surgery and recovery.

Can congenital pulmonary airway malformation be distinguished from Type I pleuropulmonary blastoma based on clinical and radiological features?

BACKGROUND

The management of congenital cystic lung lesions is controversial. Arguments for routine resection during infancy include the possibility of the lesion being Type I pleuropulmonary blastoma (PPB) rather than a cystic congenital pulmonary airway malformation (CPAM). We aimed to identify clinical and radiological features that might distinguish between CPAM and PPB and to develop a diagnostic algorithm based on these features.

METHODS

All recorded cases of Type I PPB were retrieved from the International PPB Registry and compared with an institutional cohort of children undergoing resection of CPAM (2002-2013) that was noted at some stage to be at least partially cystic. Regression models were created to identify variables that might differentiate CPAM from PPB. Odds ratio (OR) and positive predictive value (PPV) were calculated for each variable and a decision algorithm developed.

RESULTS

In 112 cases of Type I PPB and 103 of CPAM, factors favoring a diagnosis of CPAM included prenatal detection (OR 89.4), systemic feeding vessel (OR 61.7), asymptomatic (OR 8.0), and hyperinflated lung (OR 6.6). Factors favoring a diagnosis of PPB included bilateral or multisegment involvement (OR 2.4). A decision algorithm that helps to identify lesions requiring resection and those which can be safely observed is presented.

CONCLUSION

Clinical and radiological features can help to differentiate between CPAM and PPB. Our algorithm allows identification of children at higher risk of PPB in whom we would recommend resection and those at low risk in whom continued close observation is safe.

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.

The argument for operative approach to asymptomatic lung lesions

Antenatal detection of congenital pulmonary airway malformations (CPAM) has improved immeasurably from its initial application in the 1980s and probably encompasses >80% of all such lesions. Accurate diagnosis still remains less reliable and definitive diagnosis requires detailed anatomical imaging (typically with CT scan) in the post-natal period. About 10% of all lesions will present with symptoms during the neonatal period and the choice of surgical intervention is then easy. For those that remain asymptomatic then there is still a degree of controversy about elective surgical resection. This article presents the case for elective surgery within the first year of life and aims to quantify the risks of non-intervention such as abscess, empyema, recurrent pneumonia, air-leak, and pneumothorax and various types of malignancy in such cases. The current surgical approach now includes both open muscle-sparing thoracotomy and thoracoscopic resection.

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.

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.

Congenital lung malformations: informing best practice

The management of congenital lung malformations is controversial both in the prenatal and postnatal periods. This article attempts to inform best practice by reviewing the level of evidence with regard to prenatal diagnosis, prognosis, and management and postnatal management, including imaging, surgical indication, surgical approach, and risk of malignancy. We present a series of clinically relevant statements along those topics and analyze the evidence for each. In the end, we make a plea for an adequate description of the lesions, both before and after birth, which will allow future comparisons between management options and the initiation of prospective registries.

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.

Pleuropulmonary blastoma type III extended into the left atrium in a 16-month old boy

Pleuropulmonary blastoma is an uncommon paediatric neoplasm. Approximately 300 cases have been reported. In seven tumours, extension involved the left heart. Type III occurs typically at ages 3 or 4 years. We report this very unusual case of extensive disease in a 16-month old male patient. Chest computerized tomography revealed a mass extending into the right hemithorax from the posterior mediastinum and propagating inside the left atrium through the right pulmonary veins. Echocardiography showed a huge flexible mass occupying almost all of the left atrium cavity and intermittently prolapsing through the mitral valve. Two preoperative chemotherapy courses of ifosfamide, vincristine, actinomycin D and doxorubicin were administered at 3-week intervals. The patient was placed on cardiopulmonary bypass, cardiac arrest and the left atrium was opened. The tumour and orifice of the inferior right pulmonary vein were resected and the normal free borders reconstructed. A large mass occupying the right pleural space was removed. Seven additional courses of chemotherapy were given. In a 'second-look' surgery 6 months later, through a right thoracotomy, the residual mass at the posterior mediastinum was resected. The child received four additional courses of chemotherapy. After 12 months of the initial resection, there is no evidence of recurrence.

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.

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.