Perinatal Thoracic Mass Lesions: Pre- and Postnatal Imaging

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.

Magnetic resonance imaging for congenital lung malformations

Congenital lung malformations are most often identified on prenatal US screening. Fetal MRI is often performed to further evaluate these lesions. Although some of these lesions might cause prenatal or early postnatal symptoms that require urgent management, the majority are asymptomatic at birth and might be subtle or invisible on chest radiographs. Postnatal imaging is frequently deferred until 3-6 months of age, when surgery or long-term conservative management is contemplated. High-quality imaging and interpretation is needed to assist with appropriate decision-making. Contrast-enhanced chest CT, typically with angiographic technique, has been the usual postnatal imaging choice. In this review, the author discusses and illustrates the indications and use of postnatal MR imaging for bronchopulmonary malformations as well as some differential diagnoses and the advantages and disadvantages of MR versus CT.

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 lung interstitial tumor: Prenatal presentation of a rare fetal malignancy

Fetal lung interstitial tumor (FLIT) is a rare fetal malignancy that is typically diagnosed in the postnatal period, or, if recognized prenatally can mimic a benign lesion such as congenital pulmonary airway malformation. We present the earliest case of a FLIT tumor described by ultrasound and MRI at 26 weeks of gestation. Our case highlights features suggestive of FLIT including presentation later in gestation in combination with findings on fetal MRI such as a solid appearance with radiating curved bands of high signal within and along the periphery of the lesion (not as intensely high signal as the typical CPAM), possibly detailing a radiographic signature for these tumors. The role of betamethasone for these tumors is not known.

Undiagnosed and Rare Diseases in Perinatal Medicine: Lessons in Context and Cognitive Diagnostic Error

Critically ill neonates experience high rates of morbidity and mortality. Major diagnostic errors are identified in up to 20% of autopsied neonatal intensive care unit deaths. Neonates with undiagnosed or rare congenital disorders may mimic critically ill neonates with more common acquired conditions. The context of the diagnostic evaluation can introduce unique biases that increase the likelihood of diagnostic error. Herein is presented a framework for understanding diagnostic errors in perinatal medicine, and individual, team, and systems-based solutions for improving diagnosis learned through the implementation and administration of an undiagnosed and rare disease program.

The rare solid fetal lung lesion with T2-hypointense components: prenatal imaging findings with postnatal pathological correlation

BACKGROUND

At fetal MR, congenital lung lesions are usually T2 hyperintense with respect to normal lung parenchyma. Some lesions, however, demonstrate unusual patterns of T2 hypointensity, sometimes in a rosette-like pattern. These lesions usually present a diagnostic conundrum.

OBJECTIVE

To evaluate the imaging findings and pathological characterization of fetal solid lung lesions with elements showing T2-hypointense signal with respect to lung.

MATERIALS AND METHODS

This is a retrospective study of lung lesions with elements showing T2 hypointensity treated prenatally and postnatally at our center and with available pathological evaluation. Prenatal imaging evaluation included US and MR; postnatal evaluation consisted of pathological examination of the lesion. We also performed prenatal and postnatal chart review.

RESULTS

Six cases met study criteria. Areas of decreased echogenicity/T2-hypointense signal were more conspicuous at MR than US. At pathology, these areas correlated with immature parenchymal development and increased mesenchymal tissue. Five of these lesions were congenital pulmonary airway malformations (CPAM); one was a congenital peribronchial myofibroblastic tumor (CPMT). The lesions did not significantly change in size after steroid administration. They were all large in volume and were associated with increased amniotic fluid. All cases of CPAM underwent premature delivery (one of them weeks after fetal surgical resection of the lesion for worsening hydrops); the fetus with CPMT was delivered at term. The neonate with CPMT succumbed shortly after birth secondary to lung hypoplasia; the remaining five neonates survived.

CONCLUSION

The differential diagnoses of prenatal lung lesions that contain unusual T2-hypointense elements include CPAM and CPMT. The T2-hypointense areas appear to correlate with increasing degree of immaturity at histology. None of the lesions significantly changed in size after prenatal administration of steroids. All cases with CPAM lesions did well despite persistent polyhydramnios and premature birth. The single case of CPMT, however, resulted in neonatal demise shortly after birth secondary to pulmonary hypoplasia. It is important that fetal radiologists, obstetricians and fetal surgeons alike are aware of these lesions so that appropriate diagnosing and parental counseling can be reached.

Highlights on MRI of the fetal body

Fetal MRI is a level III diagnostic tool performed subsequently a level II prenatal ultrasound (US), in cases of inconclusive ultrasonographic diagnosis or when a further investigation is required to confirm or improve the diagnosis, to plan an appropriate pregnancy management. Fetal MRI plays an increasingly important role in the prenatal diagnosis of fetal neck, chest and abdominal malformations, even if its role has been amply demonstrated, especially, in the field of fetal CNS anomalies. Due to its multiparametricity and multiplanarity, MRI provides a detailed evaluation of the whole fetal respiratory, gastrointestinal and genitourinary systems, especially on T2-weighted (W) images, with a good tissue contrast resolution. In the evaluation of the digestive tract, T1-W sequences are very important in relation to the typical hyperintensity of the large intestine, due to the presence of meconium. The objective of this review is to focus on the application of fetal MRI in neck, chest and abdominal diseases.