Clinico-pathological characteristics of congenital pulmonary lymphangiectasis: report of two cases

Contribution of fetal magnetic resonance imaging in fetuses with congenital heart disease

BACKGROUND

Increasing evidence supports an association among congenital heart disease (CHD), structural brain lesions on neuroimaging, and increased risk of neurodevelopmental delay and other structural anomalies. Fetal MRI has been found to be effective in demonstrating fetal structural and developmental abnormalities.

OBJECTIVE

To determine the contribution of fetal MRI to identifying cardiovascular and non-cardiovascular anomalies in fetuses with CHD compared to prenatal US and fetal echocardiography.

MATERIALS AND METHODS

We performed a retrospective study of fetuses with CHD identified by fetal echocardiography. Exams were performed on 1.5-tesla (T) or 3-T magnets using a balanced turbo field echo sequence triggered by an external electrocardiogram simulator with a fixed heart rate of 140 beats per minute (bpm). Fetal echocardiography was performed by pediatric cardiologists and detailed obstetrical US by maternal-fetal medicine specialists prior to referral to MRI. We compared the sensitivity of fetal MRI and fetal echocardiography for the diagnosis of cardiovascular anomalies, as well as the sensitivity of fetal MRI and referral US for the diagnosis of non-cardiac anomalies. We performed statistical analysis using the McNemar test.

RESULTS

We identified 121 anomalies in 31 fetuses. Of these, 73 (60.3%) were cardiovascular and 48 (39.7%) involved other organ systems. Fetal echocardiography was more sensitive for diagnosing cardiovascular anomalies compared to fetal MRI, but the difference was not statistically significant (85.9%, 95% confidence interval [CI] 77.8-94.0% vs. 77.5%, 95% CI 67.7-87.2%, respectively; McNemar test 2.29; P=0.13). The sensitivity of fetal MRI was higher for diagnosing extracardiac anomalies when compared to referral US (84.1%, 95% CI 73.3-94.9% vs. 31.8%, 95% CI 18.1-45.6%, respectively; McNemar test 12.9; P<0.001). The additional information provided by fetal MRI changed prognosis, counseling or management for 10/31 fetuses (32.2%), all in the group of 19 fetuses with anomalies in other organs and systems besides CHD.

CONCLUSION

Fetal MRI performed in a population of fetuses with CHD provided additional information that altered prognosis, counseling or management in approximately one-third of the fetuses, mainly by identifying previously unknown anomalies in other organs and systems.

Non-immune hydrops fetalis secondary to congenital chylothorax with diffuse interstitial lung disease: a diagnostic conundrum

A Chinese male infant was born at 35 weeks weighing 2935 g to a mother with polyhydramnios and prenatal hydrops fetalis. He developed marked respiratory distress secondary to bilateral congenital chylothorax and required pleural drainage, high frequency oscillation and inhaled nitric oxide therapy. He was extubated to non-invasive ventilation by day 14. There was no bacterial or intrauterine infection, haematologic, chromosomal or cardiac disorder. He was exclusively fed medium-chain triglyceride formula. High-resolution CT showed diffuse interstitial lung disease. He received a dexamethasone course for chronic lung disease to facilitate supplemental oxygen weaning. A multidisciplinary team comprising neonatology, pulmonology, haematology, interventional radiology and thoracic surgery considered congenital pulmonary lymphangiectasia as the most likely diagnosis and advised open lung biopsy, lymphangiography or scintigraphy for diagnostic confirmation should symptoms of chylothorax recur. Fortunately, he was weaned off oxygen at 5 months of life, and tolerated human milk challenge at 6 months of life and grew well.

Pulmonary lymphangiectasis presenting as solitary pulmonary coin lesion

Pulmonary lymphangiectasis is a rare anomaly of infancy characterized by dilatation of pulmonary lymphatic vessels. It is considered to occur exclusively in young children and neonates, and pulmonary lymphangiectasis in asymptomatic adults is rare. Moreover, because chest radiography usually demonstrated the generalized congestive pattern of increased pulmonary vascularity or a reticulonodular pattern, it is extremely unusual for pulmonary lymphangiectasis to be demonstrated as a solitary nodular lesion. There were only two case reports of lymphangiectasis that developed as a nodular shadow in asymptomatic adults in English and Japanese literature. Here, we describe two cases of pulmonary lymphangiectasis that were demonstrated as solitary coin lesions in asymptomatic adults without any extrapulmonary manifestations. An 84-year-old male and a 48-year-old male were found to have a gradually increasing round pulmonary nodule. Chest computed tomography (CT) demonstrated a smooth round nodule on the lung surface, and video-assisted thoracoscopic wedge resection was performed. The nodule was a thin-walled cyst containing yellowish liquid. Histological examination of the resected lung demonstrated lymphangiectasis in the subpleural and interlobular connective tissue and no abnormal cell proliferation. Therefore, we considered that the pulmonary nodule had been formed as a result of local fluid collection in pulmonary lymphangiectasis.

Congenital pulmonary lymphangiectasia

Congenital pulmonary lymphangiectasia (CPL) is a rare but fatal disease, usually having an onset from the first few hours to days after birth. Inconsistent nomenclatures were used for CPL in the past decades. Patients often present with intractable respiratory failure, hydrops fetalis and even sudden death. The etiologies of CPL remain unclear. Previous hypotheses suggested that CPL might be caused by conditions preventing normal regression of the lymphatics after the 18th-20th week of gestation. Up-to-date biological studies on lymphatic development, lymphatic valve formation and occurrence of hydrops fetalis revealed possible causative relations with mutations of genes of the vascular endothelial growth factor receptor (VEGFR), RAS/MAPK, PI3K/AKT and NF-κB signaling pathways. Lung biopsy with subsequent histological and immunohistochemical studies is a gold standard of CPL diagnosis. Apart from symptomatic and supportive treatments, novel regimens including sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, one of the inhibitors of the pertinent signaling pathways and ethiodized oil lymphatic embolization under ultrasound-guided intranodal lymphangiography have shown encouraging short-term therapeutic effects for lymphatic anomalies. Surgical operations (lobectomy or pneumonectomy) can be the treatment of choice for patients with CPL confined to one lobe or one lung. Patients with CPL usually have a poor prognosis and often die during the neonatal period. Their prognoses are expected to improve with the development of modern therapeutic agents.

Hypoplastic left heart syndrome and the nutmeg lung pattern in utero: a cause and effect relationship or prognostic indicator?

BACKGROUND

Hypoplastic left heart syndrome (HLHS) is the third most common cause of critical congenital heart disease in newborns, and one of the most challenging forms to treat. Secondary pulmonary lymphangiectasia has been recognized in association with HLHS, an appearance described on fetal MRI as the "nutmeg lung."

OBJECTIVE

To investigate the association of fetal nutmeg lung with HLHS survival.

MATERIALS AND METHODS

A retrospective search of the fetal MRI database was performed. The nutmeg lung pattern was defined as T2 heterogeneous signal with tubular structures radiating peripherally from the hila. Postnatal echocardiograms and charts were reviewed.

RESULTS

Forty-four fetal MR studies met inclusion criteria, of which 4 patients (9%) had the nutmeg lung pattern and 3 of whom also had restrictive lesions. Mortality in this nutmeg lung group was 100% by 5 months of age. Of the 40 patients without nutmeg lung, mortality/orthotopic heart transplant (OHT) was 35%. Of these 40 patients without nutmeg lung, 5 had restriction on echo, 3 of whom died/had OHT before 5 months of age (60% of patients with restriction and non-nutmeg lung). There was a significantly higher incidence of restrictive lesions (P = 0.02) and mortality/OHT (P = 0.02) in patients with nutmeg lung compared to those without.

CONCLUSION

The nutmeg lung MR appearance in HLHS fetuses is associated with increased mortality/OHT (100% in the first 5 months of life compared to 35% with HLHS alone). Not all patients with restrictive lesions develop nutmeg lung, and outcome is not as poor when restriction is present in isolation. Dedicated evaluation for nutmeg lung pattern on fetal MR studies may be useful to guide prognostication and aid clinicians in counseling parents of fetuses with HLHS.

The fetal MR appearance of 'nutmeg lung': findings in 8 cases linked to pulmonary lymphangiectasia

BACKGROUND

A pattern of abnormal signal at fetal MRI may be seen in the setting of primary or secondary congenital lymphangiectasia, manifested as a heterogeneous appearance of the lung parenchyma and the presence of subtle T2-hyperintense branching tubular structures that emanate from the hila. We have named this pattern the nutmeg lung.

OBJECTIVE

We describe the nutmeg lung appearance seen in fetal MRI scans, with discussion of possible etiologies and outcomes in a series of eight fetuses.

MATERIALS AND METHODS

We retrospectively reviewed imaging from a database of patients demonstrating features of nutmeg lung on fetal MRI. Medical records were used to determine the postnatal diagnosis, clinical course and outcome.

RESULTS

Among the eight fetal cases of nutmeg lung, two had postnatal confirmation of primary lymphangiectasia and the remaining six had secondary lymphangiectasia, presumably secondary to congenital cardiac anomalies. There were various-size pleural effusions in all cases. Only one of the cases demonstrated hydrops fetalis.

CONCLUSION

We present the description of the nutmeg lung sign on fetal MRI as T2-hyperintense heterogeneous lungs with fluid-filled, serpiginous branching structures that extend from the pulmonary hila to the periphery of the lung, often accompanied by pleural effusions. The sign denotes findings of primary or secondary lymphangiectasia. Findings of secondary lymphangiectasia in our series were a result of cardiac insufficiency. Recognizing this sign might be helpful in the diagnostic algorithm of the fetus with abnormal lung parenchyma.

Congenital pulmonary lymphangiectasis

Congenital pulmonary lymphangiectasis (CPL) is a rare vascular malformation causing dilated lymph vessels and disturbed drainage of lymph fluid. Based on the pathogenesis and clinical phenotype it can be classified as primary or secondary CPL. Associated genetic syndromes with or without lymphedema, familial occurrence and gene mutations have been described. In utero, it may present as non-immune hydrops with pleural effusions. At birth neonates may have respiratory failure due to chylothorax and pulmonary hypoplasia, causing very high short term mortality rates. Other cases may become symptomatic any time later in childhood or even during adult life. CPL is usually diagnosed based on the combination of clinical signs, imaging and histological findings. Open-lung biopsy is considered the gold standard for the diagnosis of CPL. Treatment is primarily supportive featuring aggressive mechanical ventilation and the management of problems associated with congenital chylothorax including chest-drainage, medium-chain triglycerides (MCT) diet, and octreotide.

Imaging of thoracic lymphatic diseases

OBJECTIVE

This review will focus on radiographic description of lymphangiomas, lymphangiohemangiomas, pulmonary lymphangiomatosis, lymphangiectasis, lymphangioleiomyomatosis, lymphatic dysplasia, and traumatic lymphatic injury.

CONCLUSION

Diseases of the thoracic lymphatic system have a wide variety of unique radiographic manifestations, all of which can be explained by the underlying pathophysiology and relationship to the normal distribution of lymphatics in the chest.

Outcome of children with pulmonary lymphangiectasis

Pulmonary lymphangiectasis (PL) is a very rare developmental defect of the lungs, which has previously been reported to have a very poor prognosis. However, recent reports have suggested improved outcomes, possibly as a result of advances in neonatal and pediatric intensive care medicine. We performed a retrospective study on the outcome of children with PL between 1990 and 2008 referred to our tertiary center. Seven patients with histologically proven PL were identified over the 18-year period. Six patients presented in the neonatal period and one patient at 7 months of age, all of them requiring intensive care treatment. Three neonatal patients required extracorporeal membrane oxygenation (ECMO). Six of the seven patients did not survive including all those who received ECMO. Two of the six non-survivors died of other causes than their underlying disease. The only survivor had an antenatal diagnosis of hydrops and required in utero chest drain insertion. Postnatally he was managed with maximal medical treatment for bilateral pleural effusions and persistent pulmonary hypertension. A 7-month follow-up showed this infant to be doing well. In conclusion overall the prognosis of congenital PL remains poor. The one survivor demonstrates that this condition is survivable with aggressive intervention and as current evidence suggests gradual improvement of symptoms may occur over time, and that maximal medical treatment remains warranted.