Successful thoracoscopic resection of a giant mediastinal cyst in a newborn boy.

There are fewer reports of thoracoscopic surgical resection of mediastinal cysts in neonates. The aim of this article is to report on the feasibility of thoracoscopic resection of a large mediastinal cyst and the management of chylothorax after surgery in neonates.

INTRODUCTION

Over the past decade, thoracoscopy has become widely accepted as the method for the treatment of thoracic and mediastinal disorders for increasingly complex diagnoses and treatments.[1] However, even though there is a large body of literatures in the adult on thoracoscopic resection of large mediastinal masses via a thoracoscopic approach[23] there are fewer reports of thoracoscopic surgical resection of mediastinal tumours in neonates. The aim of this article is to report on the feasibility of thoracoscopic resection of a large mediastinal cyst and the management of chylothorax after surgery in neonates.

CASE REPORT

A newborn boy was admitted to the hospital on the 8th day after birth with increased respiration, followed by respiratory distress and hypoxaemia with paroxysmal cyanosis, with hypoxia ameliorated by lying on the affected side. This full-term infant was not found to be abnormal before delivery. On admission, chest radiographs showed a homogeneous mass occupying the entire chest [Figure 1]. Computed tomography showed a cystic mass with irregular enhancement involving the entire right thorax, and magnetic resonance imaging suggested a giant cystic mass deformity. Laboratory tests for methaemoglobin and neuroenolase were normal. This baby was admitted to the operating room at 24 days old. Thoracoscopic resection was performed using a prone position with the right side elevated, a telescope trocar was placed in the fifth intercostal space in the subscapular angle line and two operating trocars were placed in the fourth and seventh intercostal spaces in the anterior axillary line. The pneumothorax pressure was set to 4 mmHg and the flow rate was set to 3 L/min. The cyst was first incised in a small section with electric knife and the fluid was drawn out from the cyst. The cyst was diminished and subsequently removed through the enlarged trocar hole after complete resection of the cyst along the margins. The operation lasted 147 min.

Figure 1

(a and b) Magnetic resonance imaging revealed a large cystic mass in the mediastinum (c) Upper boundary of tumour (d) Lower boundary of tumour (e) Post-operative appearance (f) The figure of the cyst

Postoperatively, the child received ventilator support for 120 h with pressure-controlled mechanical ventilation. On the 3rd day after operation, an increased pleural effusion began to appear, which gradually worsened. On the 9th day after operation, the pleural effusion gradually increased to 270 ml, while the pleural effusion became milky white with positive Sudanese trichrome staining. On the 11th day after operation, the pleural drain was blocked and a replacement pleural drain was given. On the 13th day after the operation, the first intrathoracic injection of a sclerotherapy consisting of erythromycin and lidocaine plus 50% glucose was given. After the injection, the chest drain was clamped and the position was changed continuously. Since the pleural effusion persisted, two injections were given on day 16th and 19th day postoperatively. The pleural effusion disappeared on the 22nd post-operative day [Figure 2] and was subsequently fed with medium-chain fatty acid formula and discharged on the 26th post-operative day. One month later, he was fed with normal milk, but no pleural effusion appeared. Histopathological examination shows the presence of smooth muscle and enteric mucosa in the walls of the lesion, which suggests enterogenous origin [Figure 3]. Within 3 months of follow-up, the cyst recurred and chylothorax did not reappear.

Figure 2

(a) The thoracic drainage tube is blocked and the drainage fluid drops and the drainage tube is replaced (b) First time of intrapleural injection of sclerotherapy (c) Second time of intrapleural injection of sclerotherapy (d) Third time of intrapleural injection of sclerotherapy

Figure 3

Pathology suggested intestinal mucosa is attached to the smooth muscle

DISCUSSION

Mediastinal enterogenous cyst, also been called a duplication cyst, is a rare congenital malformation. It can be present with severe cardiorespiratory compromise including respiratory distress, shock, cardiac failure or arrhythmia in the neonates, which may require immediate surgical intervention soon after birth.[4] Moderate-to-severe acute respiratory distress occurs in approximate 67% of the cases, whereas all the patients have mass present on chest radiograph. About 15% of patients are asymptomatic and 40% present symptomatic by 1 month of age.

Enterogenous cysts are foregut duplication cysts occasionally associated with a vertebral defects.[5] Vertebral defects, mainly fissures or fusions, occur in about 21% of the patients.[5] These cysts may be located in prevertebral, vertebral or postvertebral positions. In this case, a vertebral defect is presented in prevertebral. In most cases, enterogenous cysts are seen in the mediastinum, peritoneal cavity, spinal canal, subarachnoid space and cerebral ventricle, but can also be seen in testis rarely.

About 36% enterogenous cysts are foregut in origin, 50% are midgut, 12% are hindgut and 2% are retroperitoneal, spinal, oropharyngeal or biliary in origin.[5] Enterogenous cysts include oropharyngeal, oesophageal, thoracoabdominal, gastric, duodenal and retroperitoneal. Oesophageal duplication represents abnormal budding of the dorsal primitive foregut and is the second most common type of foregut duplication cysts. Neurenteric cysts are oesophageal duplication cysts that extend into the spinal canal.

Histological examination of this cyst shows the presence of smooth muscle and enteric mucosa in the walls of the lesion. The mucosal type may differ from that of the gut to which it lies adjacent.

The differential diagnoses of mediastinal enterogenous in infancy include rhabdomyoma, teratoma, fibroma, bronchogenic cyst and rarely hemangioma, lipoma, thymic cyst, extralobar pulmonary sequestration, ectopic mediastinal pancreas and intrapericardial cysts.[67]

Few papers report cases of successful resection by thoracoscopy in the neonatal group. Giant mediastinal cysts of intestinal origin are not common in children with large tumours and make surgical resection difficult. Since the cysts come from the intestinal origin, it can be shrunk by aspiration of the cystic fluid. The thoracoscope can be reoriented to better expose the tumour at the mediastinal junction and to resect cysts. The operation should be started by the upper edge of the tumour. After the upper edge of the cyst has been incised, the cyst can be lifted to expose the root of the cyst and complete excision is not difficult.

Although thoracic surgery may lead to a certain incidence of chylothorax,[89] we have to avoid this complication. If chylothorax occurs, it can be treated by prohibiting diet or switched to medium-chain fatty acid-rich formula feeding to reduce fluid. The mixture of erythromycin with hypertonic glucose into the thorax can be used to accelerate pleural adhesion to cure chylothorax. The addition of lidocaine can reduce the pain of pleural reactions, and multiple injections can be given if once intrathoracic injection does not work.

CONCLUSION

Although this is an extreme case presentation of mediastinal cyst, we suggest that thoracoscopic surgery is safe for neonates. Intrathoracic curing agent injection can be used to manage post-operative chylothorax once it occurs.

Declaration of patient consent

The authors certify that they have obtained allappropriate 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 thejournal. The patients understand that their names and initials will not be published and due efforts will bemade to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.