Mediastinal enteric duplication cysts are a rare congenital malformation encountered mainly in neonates and infants. It is a distinct entity within the family of foregut duplication cysts. It can present with respiratory distress due to mass effect and hence surgical excision is the preferred treatment. Histologically, it is characterised by a double layered smooth muscle wall with intestinal lining epithelium. We report a case of mediastinal enteric duplication cyst with aberrant pancreatic tissue in a neonate due to its rarity and early presentation. A neonate presented with respiratory distress and a cystic mass in the right posterior mediastinum. The lesion was excised and on histopathological analysis the diagnosis of mediastinal enteric duplication cyst was made. Also, aberrant pancreatic tissue which has been reported rarely was noted in this case. We discuss this case and review similar cases reported in literature.
Mediastinal enteric duplication cysts are rare congenital malformations seen in neonates and infants. They are a type of foregut duplication cysts, with the other subtypes being bronchogenic and esophageal cyst [
A 29-day-old neonate weighing 4.2 kg was referred with respiratory distress since day four of life. The child was born of a nonconsanguineous marriage, at 37 weeks, with birth weight of 3.5 kg. The pregnancy and delivery were unremarkable. At admission, the child had poor activity with respiratory rate of 30/minute and pulse rate of 140/minute. Heart sounds were normal. There was decreased air entry on the right side. Biochemical investigations were normal. On the X-ray, a homogeneous opacity was seen in the right middle and lower lung fields with shift of mediastinum to the left (Figure
Chest radiograph showing a homogeneous opacity in the right middle and lower lung fields with shift of mediastinum to left.
Computed tomography scan showed a well-defined fluid attenuation lesion with broad base towards the mediastinum with few loculations.
On gross pathological examination, the cyst was greyish brown, multiloculated with wall thickness of 0.5 cm (Figure
Specimen comprising of a unilocular mass with thickened wall and inner surface markedly congested.
Microphotograph showing scanner view of the cyst wall showing double layered intestinal wall with normal intestinal mucosa and pancreatic rests within the muscularis (Hematoxylin & Eosin, 40x).
Microphotograph showing acini with cells having abundant eosinophilic granular cytoplasm (Hematoxylin & Eosin, 400x).
The term duplication cyst was first introduced in 1711 by Blassius and Bremer [
Mediastinal enteric cyst is rare and in 60% cases these cysts are diagnosed in neonates and infants with a slight male preponderance [
Mediastinal enteric cyst is usually seen in the right posterior mediastinum. It normally presents with pressure symptoms like respiratory distress due to pressure on the bronchi or lung, cough, cyanosis, retrosternal pain, and dysphagia. Children may present with recurrent chest infections. Hematemesis may occur if there is a communication with the esophagus. Ectopic gastric mucosa can be present, leading to peptic ulceration, haemorrhage, or perforation. The current case also presented with respiratory distress and showed a left mediastinal shift.
X-ray of a duplication cyst is an extremely important first-line investigation. Lateral and posterior-anterior views detect maximum lesions and show a homogeneous mass in the posterior mediastinum, usually on the right side. Ultrasonography has limited value; however, on endoscopic ultrasound, a duplication cyst appears as an anechoic or hypoechoic homogeneous cystic lesion with regular margins. Contrast-enhanced computerised tomography confirmed the presence of a well-defined homogeneously enhancing multilocular cystic lesion located in or adjacent to the wall of the part of alimentary canal.
Histopathologically, the cyst shows smooth muscle wall lined by enteric type epithelium. Ectopic gastric lining may be present. Pancreatic tissue in the mediastinum appears as a part of germ cell tumors or as pseudocysts; its presence in the wall of enteric cysts is extremely rare and to the best of our knowledge has been reported only thrice in literature [
Study | Age and sex | Duplication cyst type | Ectopic tissue type |
---|---|---|---|
Qazi et al., 1990 [ |
8 years/M | Esophageal gastroenteric duplication cyst | Pancreatic |
Prasad et al., 2002 [ |
1 day/M | Mediastinal enteric duplication cyst | Pancreatic |
Anagnostou et al., 2009 [ |
2 days/F | Mediastinal enteric duplication cyst | Pancreatic |
Present case | 4 days/M | Mediastinal enteric duplication cyst | Pancreatic |
Differentiation from other cystic lesions of the mediastinum like neurenteric cyst, pericardial cyst, thymic cyst, bronchogenic cysts, meningocele, lymphangioma, mature cystic teratoma, cystic schwannomas, cystic thymomas, and cystic tubercular lymphadenitis is important as it has important implications in further management of the patient.
Neurenteric cyst shows variable lining epithelium from respiratory, transitional to squamous. The wall shows variably thickened muscularis layer along with few nerve twigs and dystrophic neurons. There may be evidence of calcification. Pericardial cysts are usually thin walled, benign, filled with clear fluid, and lined by mesothelium. Thymic cysts may be unilocular or multilocular and are thin walled tense cysts filled with brown fluid showing pericystic fibrosis with inflammation, haemorrhage, and cholesterol clefts in the wall [
Thoracoscopic surgical excision of the cyst is the mainstay of treatment with comprehensive supportive care. This resolves the majority of the cases and is associated with minimal morbidity. Few cases which have esophageal or vertebral connections need thoracotomy. In our case, the cyst was quite large in size and expertise in thoracoscopy was not available; hence, the patient was taken up for thoracotomy. To conclude, early intervention is needed in these cases before the patient becomes symptomatic as these lesions, once symptomatic, tend to be associated with higher intraoperative complications and, if left untreated, may be complicated by perforation, obstruction, or haemorrhage. It is important for the pathologists to be aware of the vast differential diagnosis of mediastinal cysts on histopathology which would require thorough sampling to arrive at a correct diagnosis. An active search for ectopic gastric/pancreatic rests is recommended, for both its academic importance and clinical correlation in symptomatic patients.
The authors declare that they have no conflicts of interest.