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.

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.

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.

Fetal lung interstitial tumor (FLIT): A proposed newly recognized lung tumor of infancy to be differentiated from cystic pleuropulmonary blastoma and other developmental pulmonary lesions.

The differential diagnosis of congenital lung lesions includes a variety of pulmonary malformations, and uncommon or rare neoplasms such as the pleuropulmonary blastoma (PPB) and congenital peribronchial myofibroblastic tumor (CPMT). Although most of the congenital lesions have a predominantly cystic appearance, the exceptions of a more solid process are the type 3 congenital cystic adenomatoid or pulmonary airway malformation (CCAM-CPAM) and the CPMT. The clinical and pathologic features of a unique solid or mixed solid/cystic lung mass composed of immature interstitial mesenchyme in association with irregular airspace-like structures mimicking abnormal incompletely developed lung are presented in this report of 10 infants (7 males, 3 females) whose tumor-like lesions were detected in the prenatal period to 3 months of age (median, 1-day old). A lobectomy was done in all 10 infants and 1 infant received adjuvant chemotherapy. One of the surgical resections occurred as an ex utero, antenatal procedure because of fetal ascites. There have been no reported recurrences in those patients with greater than 12 months of follow-up ranging from 15 to 182 months (9 cases). Because of the morphologic resemblance of this mass-like lesion to fetal lung at 20 to 24 weeks gestation (as though any further pulmonary development was arrested in these localized lesions), we are proposing the designation of fetal lung interstitial tumor (FLIT) whose pathogenetic relationship, if any, to type 1 (cystic) pleuropulmonary blastoma remains uncertain to date.

Pulmonary blastoma as a unique cause of fatal respiratory distress in a newborn.

Pulmonary blastoma is a very rare malignant primary lung neoplasm, especially in the pediatric population. No more than 50 cases have been described in children, with none if these children diagnosed before the age of 1 month. Speculation regarding its congenital nature has been made. Although is has a uniformly poor prognosis, the case presented is that of congenital pulmonary blastoma as a unique cause of fatal respiratory distress in a neonate.