Antenatally Detected Multiple Mediastinal Enterogenous Cysts in a Newborn Presenting with Severe Cardio-Respiratory Compromise and Early Life-Saving Management.

Posterior mediastinal enterogenous cyst is a rare entity in neonate. The neonate can present with severe cardio-respiratory compromise in the form of respiratory distress, shock, cardiac failure or arrhythmia soon after birth which may require immediate surgical intervention. Antenatal screening can demonstrate the cystic mass in fetus early and can help in quick postnatal management. Multidisciplinary management with aspiration of the cysts was life-saving in the present case. Copyright:

INTRODUCTION

Posterior mediastinal enterogenous cyst (EC), a type of foregut duplication cyst, is a very rare entity in neonate. EC is formed most commonly in cervico-dorsal region in the para-vertebral position due to incomplete separation of the notochordal plate from presumptive endoderm in the 4th week of development. It may present clinically from early neonatal period to adulthood. Clinical symptoms depend on the size of the cyst and compression of surrounding structures. We describe a case, diagnosed to have mediastinal cysts in routine antenatal screening, who presented with severe cardio-respiratory compromise after birth and managed with ultrasound-guided aspiration followed by surgical excision with good outcome.

CASE REPORT

A 36+4 weeks appropriate for gestational age baby boy was born to a second gravida mother with a birth weight of 2790 g and head circumference of 33 cm (between 10th and 50th centile in Fenton's chart).[1] Mother had an uneventful antenatal and previous obstetric history. Prenatal ultrasonography at 32 weeks of gestation showed two anechoic cystic lesions, measuring 11 mm diameter behind the left atrium and 9 mm diameter in left paravertebral region. Mother was kept under close monitoring for safe delivery, but no repeat ultrasound was performed. Baby was born by normal vaginal delivery and required bag and mask ventilation for 45 seconds. APGAR score at 1, 5, and 10 minutes were 3, 6, and 8, respectively. In view of progressive respiratory worsening, the baby required rescue high-frequency oscillatory ventilation as well as inotropes for shock. Chest X-ray at birth showed a circumscribed homogenous opacity in left upper and middle lung field merging with cardiac silhouette [Figure 1]. Echocardiography was suggestive of compression of trachea, lungs, and heart chambers by the cystic structures with ejection fraction of 20%. Ultrasonography guided aspiration of the larger cyst was done at 10 hours of life and 40 ml of clear fluid was aspirated, which did not show any malignant cell. Following aspiration, there was progressive improvement of hemodynamic condition of the baby and respiratory support could be tapered off. Postaspiration, there was gradual reduction of ventilatory support, high frequency mode was changed to pressure controlled ventilation at 36 hours after aspiration and was continued on minimal pressure settings till the complete excision of the two cysts was done surgically. Ejection fraction also improved significantly over time to 55%. Baby was weaned off inotropes by the 5th day after aspiration of the cyst. After initial stabilization, contrast-enhanced computed tomography (CECT) of the chest was done which showed two collapsed cystic structures in the posterior mediastinum [Figure 1] compressing on trachea with shifting of the aorta. After hemodynamic stabilization, both cysts were excised surgically on day 8 of life and a left-sided chest drain was left in-situ. Intraoperatively, larger cyst (5 cm × 3 cm) was related to left subclavian artery, arch of aorta, and left atrium, while the smaller one (3 cm × 2 cm) was on the right side of midline and related to the right vagus nerve. Cysts were receiving blood supply directly from the descending thoracic aorta. The baby was extubated on the 2nd postoperative day, was kept on noninvasive mode of ventilation and later weaned to bubble CPAP in another 36 hours time. Baby was successfully weaned off respiratory support by 72 hours postoperatively. On the 6th postoperative day, he developed tachypnea. Chest X-ray showed left lower lobe collapse with left-sided diaphragmatic palsy and ultrasonography showed no movement of left dome of the diaphragm. Pneumonia and sepsis were ruled out. Baby remained hemodynamically stable and was accepting feed well. He was closely followed up for another 15 days, and there was progressive improvement of the left diaphragmatic movement without any active intervention. Baby started gaining weight satisfactorily and was discharged in the stable condition on day 26 of life on full breastfeed.

Figure 1

Roentogenogram of chest anterior-posterior view (a) and lateral view (b) showing a circumscribed homogenous opacity in the left upper and middle zones of lung field, merging with cardiac silhouette medially and anteriorly (before aspiration). Contrast-enhanced computed tomography of the thorax showing mediastinal window (c) and lung window (d) both of which show the nonhomogenous cystic mass on both sides of the posterior mediastinum closely related to great vessels (after initial aspiration)

Histopathology of the surgically excised cystic structure showed tall columnar lining epithelium, with cyst wall being composed of circular and longitudinal muscle layers. The cyst wall was histologically similar to the small intestine with all its layers and had focal lympho-plasmacytic infiltrates [Figure 2]. Hence, the diagnosis of posterior mediastinal EC was confirmed.

Figure 2

(a) Photomicrograph shows cyst wall with irregular smooth muscle layer and lining of intestinal tall columnar epithelium (H and E, ×4). (b) Photomicrograph shows intestinal tall columnar lining epithelium (H and E, ×20)

DISCUSSION

As per the “Split Notochord Theory” by Bentley and Smith, EC arises from abnormal budding of dorsal primitive foregut. In the 3rd week of embryonic life, the developing notochord fuses with endoderm and again in the 4th week, it separates from the endoderm. During this process, persistence of any adhesion between the two structures may result in the formation of traction diverticula and duplication cysts as well as vertebral defects. ECs, first described by Blassius and Bremer in 1711, are broadly classified into isolated foregut duplication cysts (complete separation of primitive notochord from the endoderm) and neuro-enteric cyst (duplication cyst associated with vertebral anomaly).[2] Histologically ECs are classified on the basis of their resemblance to epithelium of gastrointestinal tract into foregut, midgut and hindgut cysts. In a large review study of 495 duplication cysts, half were midgut, one third were foregut, and 12% were hindgut cysts in origin.[3] Our case was an isolated enteric duplication cyst in the thoracic cavity without any vertebral malformation.

Foregut duplication cysts are seen in close proximity to the esophagus and may also present anywhere in the posterior mediastinum, most commonly in the paravertebral position. The duplication cysts are usually benign and asymptomatic presenting later in life and are detected incidentally on X-ray done because of other conditions. The mediastinal enteric cysts relatively present earlier and 40% of large mediastinal ECs become symptomatic in the neonatal period.[3] They present with dyspnea or stridor due to compression on trachea/bronchi or lung and when the size is too large, cardiogenic shock may also develop due to the compression of heart chambers as well as great vessels as in index case.[4] Contrary to the earlier studies, some reports have shown that large size of cysts may have a prognostic value as these cysts tend to be detected earlier and if intervened judiciously, reduces risk of future complications but risk benefit ratio must be estimated before surgery as malignancy is rarely reported.[3]

Chest X-ray may show incidental mass in the posterior mediastinum. CECT chest usually clinches the diagnosis and is also required before planning surgical intervention. Magnetic resonance imaging of spine may be required if spinous involvement is suspected and Technetium99 scintigraphy, for suspected perforation and bleeding.[5]

Prenatal surgical intervention in the form of cyst drainage or shunting may be performed if cysts are large and causing hydrops or pulmonary hypoplasia. Antenatal demonstration of cysts may help in early and proper planning of delivery in a tertiary care center with early involvement of multidisciplinary postnatal management.[6] Postnatally, surgical intervention is done usually when the baby presents with obstructive symptoms. Total excision of the cyst is the surgery of choice. The index case had respiratory failure, shock at birth, and was managed adequately in the neonatal intensive care unit with immediate ultrasound-guided aspiration of the cyst followed by surgical excision of the cyst.

Only two cases of EC have been reported presenting as mediastinal mass from India till date.[78] One neonate had isolated EC presenting on day 22 of life while the other presented on day 1 of life with vertebral anomaly. The index case had antenatally detected isolated EC with very early presentation immediately after birth.

At 24 months, child is now asymptomatic, gaining weight, and has age appropriate developmental milestone.

To conclude, large antenatally detected ECs may present with neonatal hemodynamic compromise. A quick ultrasound-guided aspiration of the cysts is life-saving till definitive surgery is performed.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.