The role of 3-dimensional reconstruction imaging in bronchopulmonary sequestration.

Bronchopulmonary sequestration is a congenital abnormality characterized by non-functioning lung tissue, abnormal connection with the tracheobronchial tree and anomalous systemic arterial supply. Although considered a rare phenomenon presenting early in life, sequestration may also present with recurrent chest infections in late adulthood. Additionally, bronchopulmonary sequestration may rarely be incidentally encountered during thoracic surgery. Several subtypes exist including intralobar, extralobar and hybrid bronchopulmonary sequestration (congenital pulmonary artery malformation). Surgical resection is curative and serves as the treatment of choice for symptomatic patients. Radiological imaging prior to surgery is essential in these patients because the arterial supply may be anatomically complex, and aberrant artery branches are common. Utilization of virtual 3-dimensional remodelling and computed tomography reconstruction imaging can not only establish a diagnosis of bronchopulmonary sequestration but can also optimize preoperative planning. This approach will ultimately prove useful in anticipating surgically challenging steps and avoiding unnecessary intraoperative complications. We present a video tutorial on the role of 3-dimensional reconstruction imaging in bronchopulmonary sequestration and a step-by-step guide for performing a right robotic-assisted surgical resection of an S2 hybrid bronchopulmonary sequestrated segment. This case is followed by a second case of intralobar bronchopulmonary sequestration encountered incidentally during thoracic surgery.

Integrative analysis of bulk and single-cell RNA sequencing reveals the gene expression profile and the critical signaling pathways of type II CPAM.

BACKGROUD: Type II congenital pulmonary airway malformation (CPAM) is a rare pulmonary microcystic developmental malformation. Surgical excision is the primary treatment for CPAM, although maternal steroids and betamethasone have proven effective in reducing microcystic CPAM. Disturbed intercellular communication may contribute to the development of CPAM. This study aims to investigate the expression profile and analyze intercellular communication networks to identify genes potentially associated with type II CPAM pathogenesis and therapeutic targets. METHODS: RNA sequencing (RNA-seq) was performed on samples extracted from both the cystic area and the adjacent normal tissue post-surgery in CPAM patients. Iterative weighted gene correlation network analysis (iWGCNA) was used to identify genes specifically expressed in type II CPAM. Single-cell RNA-seq (scRNA-seq) was integrated to unveil the heterogeneity in cell populations and analyze the communication and interaction within epithelial cell sub-populations. RESULTS: A total of 2,618 differentially expressed genes were identified, primarily enriched in cilium-related biological process and inflammatory response process. Key genes such as EDN1, GPR17, FPR2, and CHRM1, involved in the G protein-coupled receptor (GPCR) signaling pathway and playing roles in cell differentiation, apoptosis, calcium homeostasis, and the immune response, were highlighted based on the protein-protein interaction network. Type II CPAM-associated modules, including ciliary function-related genes, were identified using iWGCNA. By integrating scRNA-seq data, AGR3 (related to calcium homeostasis) and SLC11A1 (immune related) were identified as the only two differently expressed genes in epithelial cells of CPAM. Cell communication analysis revealed that alveolar type 1 (AT1) and alveolar type 2 (AT2) cells were the predominant communication cells for outgoing and incoming signals in epithelial cells. The ligands and receptors between epithelial cell subtypes included COLLAGEN genes enriched in PI3K-AKT singaling and involved in epithelial to mesenchymal transition. CONCLUSIONS: In summary, by integrating bulk RNA-seq data of type II CPAM with scRNA-seq data, the gene expression profile and critical signaling pathways such as GPCR signaling and PI3K-AKT signaling pathways were revealed. Abnormally expressed genes in these pathways may disrupt epithelial-mesenchymal transition and contribute to the development of CPAM. Given the effectiveness of prenatal treatments of microcystic CPAM using maternal steroids and maternal betamethasone administration, targeting the genes and signaling pathways involved in the development of CPAM presents a promising therapeutic strategy.

Retrospective evaluation of neonates with fatal congenital lung malformation: A single center 15-year forensic autopsy experience.

Congenital lung malformation (CLM) is a leading cause of infant mortality. Clinical methods for diagnosing CLM mainly rely on computed tomography, magnetic resonance imaging, ultrasonography, and Doppler. However, forensic identification of the cause of death in neonates is challenging. Unequivocal classification criteria for CLM are missing as its forensic identification is ambiguous. Therefore, we aimed to analyze neonatal death cases at our center to assist in identifying those with congenital lung malformation. This retrospective study identified and classified the causes of deaths of neonates autopsied between January 2008 and April 2023. All cases born alive and died within 28 days with a clear time of death were selected, and forensic experts reviewed their records. The manner, cause of death, and other characteristics were noted and discussed. This retrospective study reveals a steady increase in autopsy cases from 2008 to 2015, attributed to improved parental consent, heightened awareness of autopsy importance, and enhanced medical resources. However, a subsequent decline post-2015 is observed, potentially influenced by advancements in medical technology and prenatal examination protocols. The top causes of neonatal mortality include respiratory diseases, asphyxia, congenital dysplasia, and fetal distress. Congenital lung malformations, particularly bronchopulmonary malformations, constitute a significant portion of congenital anomalies. This study underscores the importance of standardized autopsies and histopathological examinations in diagnosing and understanding CLM. Future research should focus on expanding case collections and elucidating the genetic basis of CLM to improve forensic management and outcomes.

Thoracoscopic surgery for rare congenital pulmonary airway malformations in adults: a decade of retrospective study.

Background: Congenital pulmonary airway malformation (CPAM) is a rare benign deformity of the lungs in adults. Our study aimed to evaluate the clinical features and compare the effect of thoracoscopic lobectomy and wedge resection for adult CPAMs. Methods: This was a retrospective study including eighteen adults with CPAMs recruited between 2013 and 2023. Radiological scans and pulmonary function test (PFT) were performed before operation. All the patients were treated with thoracoscopic approach, which were categorized into groups of lobectomy and wedge resection. The baseline, preoperative, and operative data were evaluated and analyzed. Results: Four males and fourteen females were diagnosed with CPAMs at a median age of 57.5 years. Cough was the main symptom, reported by 55.6% of the patients. CPAMs were always initially misdiagnosed as other conditions due to heterogeneous computed tomography (CT) characteristics. The mean of PFT results showed normal (>80% predicted) in forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and FEV1 to FVC ratio (FEV1/FVC), but less than 70% predicted in forced expiratory flow (FEF) at 25-75%, 50% and 75% of FVC. All patients underwent video-assisted thoracic surgery (VATS) with a total of nine wedge resections and nine lobectomies. Age at surgery varied statistically between the two groups. Whereas, duration of surgery, blood loss, postoperative drainage, days of drainage, days of hospitalization and postoperative complications showed no statistical difference between the two groups. There were 27.8% of the lesions showing CPAMs mixed with other diseases during histological evaluations. Conclusions: CPAM in adults showed a complex presentation in terms of clinical symptoms, imaging performance and pathological findings. Half of the patients were detected with small airway dysfunction preoperatively. Thoracoscopic lobectomy and wedge resection for the treatment can achieve satisfactory short-term outcomes.

Needle Fetal Thoracoscopy: A Technique to Assist with Ultrasound-Guided Placement of Challenging Thoracoamniotic Shunts.

INTRODUCTION: Fetal thoracoamniotic shunts are common lifesaving interventions but frequently require replacement. Needle fetal thoracoscopy is a technique that uses standard thoracoamniotic shunt introducer sheaths to permit direct visualization and even instrument manipulation during shunt deployment to facilitate optimal positioning and primary shunt function in the most challenging cases. CASE PRESENTATION: In this study, 5 patients who underwent needle fetal thoracoscopy-assisted thoracoamniotic shunt placement were reviewed. Three patients with large, macrocystic congenital pulmonary airway malformations (CPAMs) with evidence of worsening mediastinal shift and/or hydrops and 2 patients with large chylothorax with fetal hydrops were treated. Four cases had previous shunts that failed due to poor sonographic visualization during initial placement, cyst septations, shunt obstruction, or dislodgment. Needle fetal thoracoscopy was used to disrupt cyst walls and septations, clear hematoma, and confirm the optimal initial position of the shunt. In this series, 1 severe CPAM patient with a short cervix developed preterm labor postoperatively resulting in neonatal demise. The remaining 4 patients experienced resolution of hydrops and progressed to successful delivery with excellent neonatal outcomes. CONCLUSION: Needle fetal thoracoscopy is a procedure that may be selectively deployed in challenging thoracoamniotic shunt cases impacted by recurrent failure, poor sonographic windows, and challenging fetal positioning.

Prognosis of infants with congenital pulmonary airway malformations after surgery: a short and mid-term evaluation.

OBJECTIVE: To investigate the postoperative pulmonary function, imaging descriptions and complications in infants with congenital pulmonary airway malformations (CPAM), and to examine the impact of different surgical resections on the prognosis of infants. METHODS: Data of 30 infants with CPAM who underwent surgery at the department of Pediatric Surgery, Guangzhou Women and Children's Medical Center from June 2021 to June 2022 were retrospectively collected and analyzed. The pulmonary function indexes of the infants during the first month and first year after surgery were analyzed to assess prognosis. Pulmonary function data from healthy individuals at similar age were collected as a control group. RESULTS: The post-operative short-term pulmonary function was recovered to a normal level in 26.7% cases of 30 CPAM infants, with a decrease in tidal volume (VT), ratio inspiratory time to expiratory time (TI/TE), time to peak tidal expiratory flow as a proportion of expiratory time (TPTEF/TE), volume to peak expiratory flow as a proportion of exhaled volume (VPEF/VE) and mean expiratory flow as a proportion of mean inspiratory flow (MEF/MIF) when compared to the control group (all P<0.01). One year after operation, 25 CPAM infants received pulmonary function tests and 52% of them had indexes at normal level. There was no statistically significant difference in results of pulmonary function test between infants who received lobectomy and those who received segmentectomy (P>0.05). The postoperative complication rate was 26.7%. CONCLUSION: Over half of CPAM infants have normalized lung function one year after operation and the choice of lobectomy and segmentectomy had no significant difference on prognosis of infants.

Surgical Management of Congenital Pulmonary Airway Malformations (CPAM) in an Infant and a Toddler: Case Report Depicting Two Distinct Surgical Techniques With Successful Outcomes.

Congenital pulmonary airway malformations (CPAM) compose the major part of congenital lung malformations (CLM) and have traditionally been treated by pulmonary lobectomy. In terms of surgical strategy, lobectomy has conventionally been the preferred treatment for CPAM localized to a single lobe. More recently, alternative approaches including lung-sparing resections (LSR), such as wedge or non-anatomic resections and segmentectomy, have been suggested. In asymptomatic CPAM early surgical resection is often shown to reduce infection and malignancy development. We describe two patients who were diagnosed with CPAM when being evaluated for respiratory tract infection. Patient 1 (P1) was a two-month-old infant weighing 4 kg with glucose-6-phosphate dehydrogenase (G6PD) deficiency and Patient 2 (P2) was a toddler aged one year, nine months weighing 9 kg. P1 underwent LSR for the CPAM diagnosed in the left upper lobe of the lung with conventional mechanical ventilation whilst right upper lobectomy was performed in P2 using one/single lung ventilation. In both cases, LSR and right upper lobectomy led to an uneventful postoperative recovery with no complications reported.

Assessment of mediastinal shift angles in congenital pulmonary airway malformation: a new fetal magnetic resonance imaging indicator of congenital lung disease.

BACKGROUND: The mediastinal shift angle is a new fetal magnetic resonance imaging (MRI) index that is reportedly correlated with postnatal survival in fetuses with congenital diaphragmatic hernia. However, its correlation in patients with congenital pulmonary airway malformation (CPAM) has not been assessed. OBJECTIVE: This study aimed to establish a normal range for the right/left mediastinal shift angles, to evaluate the mediastinal shift angle in fetuses with CPAM, to compare the mediastinal shift angle with the CPAM volume ratio, and to evaluate the predictive value of the mediastinal shift angle measurements. MATERIALS AND METHODS: To establish the normal range, we measured the mediastinal shift angle bilaterally in 124 fetuses without any lung abnormality (the control group). Subsequently, the mediastinal shift angle was measured in 32 fetuses pathologically diagnosed with CPAM. Moreover, the mediastinal shift angle and CPAM volume ratio were compared using fetal MRI. RESULTS: The mean values for the right/left mediastinal shift angles were 18.6°/26.3° and 39.2°/35.9° for control fetuses and fetuses with CPAM, respectively. The mediastinal shift angle and the CPAM volume ratio showed a positive statistical correlation. The area under the curve demonstrated high discriminatory accuracy for the mediastinal shift angle (0.76). CONCLUSION: The mediastinal shift angle has potential to replace the CPAM volume ratio for evaluating the severity of CPAM in fetal MRI.

The Effect of Steroids on Prenatally Diagnosed Lung Lesions.

BACKGROUND: Open fetal resection for large lung lesions has virtually been replaced by maternal steroid administration. Despite this paradigm shift, little is known about the effects steroids have on lung lesion growth in utero. METHODS: A 10-year retrospective review of all prenatally diagnosed lung lesions cared for at our fetal care center was performed. We evaluated the effects of prenatal steroids on congenital pulmonary airway malformation (CPAM)-volume-ratio (CVR), distinguishing change in CVR among CPAMs, bronchopulmonary sequestrations (BPS), and bronchial atresias. We also correlated fetal ultrasound and MRI findings with pathology to determine the accuracy of prenatal diagnosis. RESULTS: We evaluated 199 fetuses with a prenatal lung lesion. Fifty-four (27 %) were treated with prenatal steroids with a subsequent 21 % mean reduction in the CVR (2.1 ± 1.4 to 1.1 ± 0.4, p = 0.003). Fetuses with hydrops and mediastinal shift who were treated with steroids rarely had resolution of these radiographic findings. Postnatal pathology was available for 91/199 patients (45.7 %). The most common diagnosis was CPAM (42/91, 46 %), followed by BPS (30/91, 33 %), and bronchial atresia (14/91, 15 %). Fetuses who received steroids and had pathology consistent with CPAM were more likely to have a reduction in their CVR (p = 0.02). Fetal ultrasound correctly diagnosed the type of lung lesion in 75 % of cases and fetal MRI in 81 % of cases. CONCLUSIONS: Prenatally diagnosed CPAMs are more likely to respond to maternal steroids than BPS or bronchial atresias. Knowing the diagnosis in utero could aid to steward steroid usage, however, fetal imagining modalities are not perfect in distinguishing subtype. LEVEL OF EVIDENCE: III.

Cytomorphologic and immunocytochemical characterization of pediatric pleuropulmonary blastoma with a comprehensive review of the literature.

INTRODUCTION: Pleuropulmonary blastoma (PPB) is a rare, aggressive, primary intrathoracic malignancy typically seen in infancy and early childhood. Accurate distinction from congenital cystic lung lesions is crucial due to significant prognostic and therapeutic differences. Cytologic features have rarely been described. Establishing a cytodiagnosis is challenging owing to its rarity, lack of awareness, and multiple morphologic mimics. MATERIALS AND METHODS: This was a retrospective study conducted over 8 years. The histopathology and cytopathology databases were searched for all pediatric PPB cases. The corresponding cytologic samples were reviewed to identify characteristic features that can help distinguish PPB from its mimics. RESULTS: There was a total of six cases of pediatric PPB reported during the study period. Of these, four (66.7%) presented as intrathoracic, and two (33.3%) as pleural-based masses. Cytology smears showed discretely scattered and perivascular arrangements of round-oval tumor cells with background eosinophilic stromal material. The tumor cells were mildly pleomorphic (n = 3) with round nuclei, fine chromatin, inconspicuous nucleoli, and scanty cytoplasm; however, three cases showed marked anaplasia, and one each showed necrosis and rhabdoid differentiation. On immunocytochemistry (4/6), these were positive for vimentin and desmin and negative for WT1, chromogranin, SALL4, cytokeratin, CD45, and CD99. FISH (1/6) did not show N-Myc amplification. CONCLUSIONS: Knowledge of the characteristic cytomorphological and immunocytochemical features of PPB is vital to establish a prompt and accurate cytodiagnosis with appropriate clinicoradiologic correlation.

No Pathogenic DICER1 Gene Variants in a Cohort Study of 28 Children With Congenital Pulmonary Airway Malformation.

BACKGROUND: Distinguishing congenital pulmonary airway malformations (CPAMs) from pleuropulmonary blastoma (PPB) can be challenging. Previously diagnosed patients with CPAM may have been misdiagnosed and we may have missed DICER1-associated PPBs, a diagnosis with important clinical implications for patients and their families. To gain insight in potential misdiagnoses, we systematically assessed somatic DICER1 gene mutation status in an unselected, retrospective cohort of patients with a CPAM diagnosis. METHODS: In the Amsterdam University Medical Center (the Netherlands), it has been standard policy to resect CPAM lesions. We included all consecutive cases of children (age 0-18 years) with a diagnosis of CPAM between 2007 and 2017 at this center. Clinical and radiographic features were reviewed, and DICER1 gene sequencing was performed on DNA retrieved from CPAM tissue samples. RESULTS: Twenty-eight patients with a surgically removed CPAM were included. CPAM type 1 and type 2 were the most common subtypes (n = 12 and n = 13). For 21 patients a chest CT scan was available for reassessment by two pediatric radiologists. In 9 patients (9/21, 43%) the CPAM subtype scored by the radiologists did not correspond with the subtype given at pathology assessment. No pathogenic mutations and no copy number variations of the DICER1 gene were found in the DNA extracted from CPAM tissue (0/28). CONCLUSIONS: Our findings suggest that the initial CPAM diagnoses were correct. These findings should be validated through larger studies to draw conclusions regarding whether systematic DICER1 genetic testing is required in children with a pathological confirmed diagnosis of CPAM or not. LEVEL OF EVIDENCE: Level IV.

Management and Outcomes of Patients With High-Risk (Congenital Lung Malformation Volume Ratio≥ 1.6) Congenital Lung Malformations.

INTRODUCTION: Congenital lung malformations (CLMs) have a variable natural history. Larger lesions with CLM volume ratio (CVR) ≥ 1.6 are associated with hydrops and fetal mortality. The purpose of this study is to describe the management and outcomes of high-risk (CVR ≥ 1.6) CLM patients. METHODS: A retrospective cohort study was performed for all fetuses evaluated between May 2015 and May 2022. Demographics, prenatal imaging factors, prenatal and postnatal treatment, and outcomes were collected. Descriptive statistics were used to compare the cohorts. RESULTS: Of 149 fetal CLM patients referred to our fetal center, 21/149 (14%) had CVR ≥ 1.6. One CLM patient had intrauterine fetal demise, and 2 patients were lost to follow-up. Of the remaining 18 patients, 11/18 (67%) received maternal steroids. Seven out of 18 patients (39%) underwent resection at the time of delivery with 1/7 (14%) undergoing exutero intrapartum treatment (EXIT)-to-resection, 5/7 (71%) undergoing EXIT-to-exteriorization-to-resection, and 1/7 (14%) undergoing a coordinated delivery to resection; among those undergoing resection, there were 2 fatalities (28.5%). Seven out of 18 (39%) patients required urgent neonatal open lobectomies, and the remaining 4/18 (22%) patients underwent elective thoracoscopic lobectomies with no mortality. CONCLUSIONS: The natural history and outcomes of severe CLM patients remain highly variable. The EXIT-to-exteriorization-to-resection procedure may be a safe and effective approach for a subset of CLM patients with persistent symptoms of mass effect and severe mediastinal shift due to the observed decreased operative time requiring placental support observed in our study.

Antenatal diagnosis of bronchopulmonary sequestration: A case report and review of the literature.

Congenital lung malformations are a constellation of pathologies that can be diagnosed antenatally by ultrasound and fetal MRI. Ultrasound is considered the modality of choice for a routine assessment of second-trimester scans worldwide. Bronchopulmonary sequestration (BPS) and congenital pulmonary airway malformation (CPAM) are the 2 most common echogenic chest masses discovered incidentally during routine ultrasound scans in the second trimester. This paper describes BPS and differentiates it from CPAM sonographically in utero. An extensive literature search involving antenatal ultrasound is undertaken to review the most up-to-date understanding of the BPS. Furthermore, a case study at our institution and the literature review will help better describe the salient features of BPS. A 41-year-old female G3P1 visits our department for a routine second-trimester ultrasound. An echogenic lesion with a cystic component is visualized in this scan. Based on the grayscale and color imaging, this complex echogenic lesion was reported as CPAM and was referred to fetal assessment for confirmation. The fetal assessment diagnosed the lesion as BPS because of the pathognomonic feeding vessel from the thoracic aorta. Regardless of the congenital lung mass, any large mass compromising fetal well-being is an indication for intervention. The prognosis of BPS in the absence of fetal hydrops is excellent. A robust collaboration among radiologists, obstetricians, and pediatricians is required for the best outcome for the pregnancy and the neonate.

Pulmonary invasive mucinous adenocarcinoma.

Invasive mucinous adenocarcinoma (IMA) is a relatively rare subtype of lung adenocarcinoma, composed of goblet and/or columnar tumour cells containing abundant intracytoplasmic mucin vacuoles. While a majority of IMAs are driven by KRAS mutations, recent studies have identified distinct genomic alterations, such as NRG1 and ERBB2 fusions. IMAs also more frequently present as a pneumonic-like pattern with multifocal and multilobar involvement, and comparative genomic profiling predominantly shows a clonal relationship, suggesting intrapulmonary metastases rather than synchronous primary tumours. Accordingly, these unique features require different therapeutic approaches when compared to nonmucinous adenocarcinomas in general. In this article, we review recent updates on the histopathological, clinical, and molecular features of IMAs, and also highlight some unresolved issues for future studies.

Lymphangioleiomyomatosis With Atypical Presentation Following Pneumothorax: A Case Report.

Lymphangioleiomyomatosis (LAM) is a rare systemic disease that typically presents like cystic lung disease. High-resolution computed tomography (CT) is the recommended imaging technique, with cysts being the hallmark: typically multiple, well-circumscribed, thin-walled, with a variable diameter (usually <2 cm) and widespread in distribution. The gold standard for diagnosis is a biopsy. LAM should be considered in the differential diagnosis of cystic lung diseases. The authors report a case of LAM presenting with a pneumothorax, which due to its atypical imaging characteristics, mimicked another uncommon cystic disease. A multidisciplinary approach is crucial when dealing with presentations of rare diseases.

A missed foreign body aspiration masquerading as congenital pulmonary airway malformation in a nine-year-old boy: A case report and literature review.

Although airway foreign body aspiration (FBA) is a common occurrence in any age group, unrecognized and retained foreign bodies in lungs may result in severe complications, such as lung abscess or bronchiectasis. In rare cases, FBA may present with similar clinical features as many other diseases (e.g. asthma, tumor, pulmonary eosinophilia). Here, we report a rare case of missed FBA in a nine-year-old boy, whose chest CT scan was suggestive of a cavitary lesion in the left lower lobe mimicking congenital pulmonary airway malformation (CPAM). However, surprisingly, flexible bronchoscopy revealed a peanut lodged in the lateral basal segment of left lower lobe, which was subsequently retrieved by a forceps and avoided unnecessary surgical lobectomy. Therefore, FBA can mimic other disorders (e.g. CPAM), and a high index of suspicion and additional diagnostic techniques (e.g. flexible bronchoscopy) may be required to distinguish them. Additionally, FBA should be considered in the differential diagnosis of respiratory disorders in children even lack of aspiration history.

Intralobar Pulmonary Sequestration: A Case Report.

Pulmonary sequestration is a congenital lung malformation characterized by a mass of nonfunctioning lung tissue that receives its arterial supply from an aberrant systemic artery. If symptomatic, most newborns present with respiratory distress. Recurrent infection is the most common presentation after the neonatal period. It is often diagnosed prenatally and is treated with elective surgical resection between ages six and twelve months. We present a case of an infant diagnosed with congenital pulmonary airway malformation prenatally revealed to be pulmonary sequestration at the age of six months, emphasizing the need for appropriate postnatal imaging.

An Unusual Antenatal Presentation of a Mature Pericardial Teratoma Masquerading as Congenital Pulmonary Airway Malformation.

We report an antenatal presentation of a huge pericardial mature teratoma that was referred as congenital pulmonary airway malformation (CPAM) in the late third trimester of pregnancy. Initial ultrasound evaluation revealed a huge predominantly cystic lesion with mixed echogenicity in the left hemithorax. A provisional diagnosis of pleural tumor was considered in view of previous scans at 20‒28 weeks being normal and associated pleural effusion. Magnetic resonance imaging of the fetus reported the lesion to be CPAM which was supported by postnatal computed tomographic imaging done on day 2 of life. However, intraoperatively, the lesion was found to be of pericardial origin which on subsequent histopathological examination was confirmed to be mature teratoma. We recommend considering potential differential diagnosis other than CPAM, especially when the lesion is found for the first time in the late third trimester.

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

BACKGROUND: Pleuropulmonary blastoma (PPB) is an extremely rare and malignant pediatric lung tumor. Purely cystic PPB has a more favorable prognosis than solid PPB, but may be difficult to distinguish from a certain type of "benign" congenital pulmonary airway malformation before and during surgery. The influence of tumor rupture on long life prognosis has not been clarified in detail. CASE PRESENTATION: A 5-month-old boy underwent emergency transfer from another hospital due to a left thoracic cystic lesion and left pneumothorax detected on chest radiography performed for persistent wheeze and cough. Contrast-enhanced computed tomography of the chest revealed marked deviation of the mediastinum to the right due to a giant cystic lesion and pneumothorax. Thoracotomy was performed on hospital day 2. A cystic lesion had developed from the distal alveolar region of lower lobe of the left lung and the tumor showed a tiny adhesion to the left diaphragm and a tiny rupture near the adhesion. Partial lung excision including the cyst and scraping of the adhesion were performed. Histopathological investigations revealed immature blast cell-like mesenchymal cells and differentiated striated muscle cells in a dense cambium layer were found under the epithelium of the cystic lesion. Type I PPB was diagnosed. CONCLUSIONS: Surgery should be performed with the possibility of type I PPB in mind when an extrapulmonary cystic lung lesion is found. Since issues such as the pathogenesis and long-term prognosis of ruptured cases remain unclear, continued careful follow-up of this case will be required.