Enterogenous Cyst Presenting as Mediastinal Mass in a Newborn.

Duplication cyst is a rare congenital malformation. Enterogenous cyst are foregut duplication cyst with or without a vertebral defect. We report a case of a 36hr old neonate with mediastinal enterogenous cyst associated with vertebral defects. The embryology, differentials, and management of enterogenous cyst in the newborn have been discussed.

INTRODUCTION

Intrathoracic masses can be an uncommon cause of respiratory distress in term newborns. Duplication cyst can occur anywhere along the gastrointestinal (GI) tract. Midgut, particularly ileum, is the most common site. A mediastinal enterogenous cyst which is a foregut duplication cyst is a very rare entity in neonates. To the best of our knowledge, only one case of mediastinal enterogenous cyst has been reported in a newborn from India till now. We report a case of mediastinal enterogenous cyst in a neonate with respiratory distress and vertebral defects while discussing its embryology, differential, and its management.

CASE REPORT

A 36-hour-old male newborn born to a 27-year-old primigravida mother via cesarian section in view of nonprogression of labor, product of nonconsanguineous marriage with birth weight of 3600 g, length of 50 cm, and head circumference (HC) of 36 cm was admitted to referral nursery for respiratory distress, onset soon after the birth. Antenatal and intranatal periods were uneventful. The baby cried immediately after the birth. Before admission to referral nursery, the baby was managed with intravenous fluids and oxygen therapy on the 1st postnatal day elsewhere. On admission, respiratory distress was present with the rate of 86/min with upper and lower chest retractions (Downes' score: 7/10). Chest examination revealed decreased air entry and impaired breath sounds on the left side. Perfusion was maintained, and rest of the systemic examination was within normal limits. Vertebral defect was noticed at midthoracic level. The baby was kept under oxygen hood (50% FiO2). Antibiotics as per the unit protocol were started after collecting the blood cultures and sepsis screen. Sepsis screen was negative. Chest X-ray [Figure 1a] done was suggestive of well-defined large homogenous opacity in the left hemithorax with no evidence of mediastinal shift and butterfly vertebrae extending from T5 to T9. The baby was started on full-volume nasogastric feed in view of respiratory distress. Respiratory distress gradually improved and the baby weaned off oxygen by day 5 of life, but still had mild lower chest retractions and tachypnea (rate of 64–66/min) with Downes' score of 2/10. The baby was started on breastfeeding and planned for contrast-enhanced computed tomography (CECT) chest evaluation. CECT chest [Figure 1b] revealed 3.6 cm × 3.7 cm hypodense lesion in the middle and posterior mediastinum. The lesion was abutting the descending aorta medially, compressing the left main bronchus anteromedially, abutting the lateral chest wall laterally and abutting the ribs and the vertebral bodies posteriorly. Vertebral defect was noted at D5–D7 level in the form of butterfly vertebrae and scoliotic deformity. The baby underwent left posterolateral intrapleural thoracotomy with excision of the cyst on day 13 of life. Peroperatively, the cyst was found to be attached to the aorta and vertebral bodies. The cyst was completely excised [Figure 2a]. Postoperatively, the baby required oxygen (FiO2 40%) and was gradually weaned to room air by 2nd postoperative day. Feeds were restarted on 2nd postoperative day which he tolerated well. Histopathological examination [Figure 2b] of the specimen confirmed the diagnosis of enterogenous cyst. The baby was discharged on postoperative day 7 and was doing well on follow-up at 1 month (weight – 4.1 kg, HC – 37.5 cm, and length – 52 cm).

Figure 1

(a) Chest X-ray showing well-defined homogenous opacity in the left hemithorax (white arrow). (b) Computed tomography chest showing cystic lesion in the middle and posterior mediastinum (white arrow)

Figure 2

(a) Peroperative finding showing cystic structure below the left lung. (b) Histopathological examination of the cyst showing columnar lining with mild inflammation. Muscularis mucosa, subcutaneous layer, and muscularis propria can be appreciated confirming the diagnosis of enterogenous cyst

DISCUSSION

Duplication cyst (enterogenous) can arise from the GI tract, of which 36% are foregut in origin, 50% are midgut, 12% are hindgut, and 2% are retroperitoneal, spinal, oropharyngeal, and biliary in origin. Duplication cysts have well-developed smooth muscle layer and epithelial lining of GI tract and are intimately attached to some portion of GI tract. Duplication cysts can be of two types: spherical (65%) and tubular (35%). Around 21% of patients have associated vertebral defect mainly cleft or fused vertebrae. About 15% of patients are asymptomatic and 40% present by 1 month of age.

Foregut duplication cysts include oropharyngeal, esophageal, thoracoabdominal, gastric, duodenal, and retroperitoneal. Midgut cysts include jejunal, ileal, ileocecal, appendicial, cecal, and colonic. Hindgut cysts arise from the rectum and colon. Among foregut cysts, bronchogenic cysts are most common. These have cartilaginous component in cystic wall and represent abnormal budding of ventral primitive foregut. Esophageal duplication represents abnormal budding of the dorsal primitive foregut and is the second most common type of foregut duplication cysts. Neurenteric cysts are esophageal duplication cysts that extend into the spinal canal.

The most accepted theory for foregut duplication cyst is that of the “split notochord syndrome” with persistence of a neurenteric canal, i.e., the notochord and foregut fail to separate. In this connecting area, cyst or diverticula of foregut might develop. In posterior enterogenous cysts, only an intermediate part of the embryonic fistula or diverticulum persists. These cysts may be prevertebral, vertebral, or postvertebral in position. Histological examination of the remnant usually 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. Approximately 67% of patients present with moderate-to-severe acute respiratory distress, and all have mass present on chest radiograph.

Few case reports have been published in literature with enterogenous cyst in newborns. Languepin et al. reported a case of a 16-day-old neonate with intraspinal enterogenous cyst developing spastic quadriparesis with bilateral phrenic nerve palsy.[1] Similarly, a neonate with enterogenous cyst of the spinal cord with associated intestinal reduplication, vertebral anomalies, and a dorsal dermal sinus was reported from England, which later on developed meningitis.[2] Morabito et al. reported a newborn with large rhinopharyngeal and oropharyngeal enterogenous cyst, associated with an osseous defect of the basiocciput, called canalis basilaris medianus.[3] Luis et al. reported a neonate with sternal cleft and an enterogenous cyst from Spain.[4] Enterogenous cyst rarely presents as mediastinal mass in neonates as was in our case. One case report of a neonate with mediastinal enterogenous cyst has been reported from India. This baby presented with respiratory distress on day 22 and had no vertebral defect.[5] In contrast, our baby had vertebral defects and became symptomatic on day 1.

CT scan does not differentiate it from other esophageal lesions. Duplication cysts have a smooth appearance with no enhancement with contrast. Differentiating the duplication cyst is solely based on the histopathological criteria. Prompt excision is the treatment of choice.

CONCLUSION

The mediastinal enterogenous cyst is a rare cause of mediastinal mass in newborn presenting as respiratory morbidity. CECT may not be able to differentiate neurenteric cysts from the enterogenous cysts. They can be differentiated from each other solely on the basis of clinical presentation, associated vertebral defects, and histopathological examination.

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Conflicts of interest

There are no conflicts of interest.