Purpose: The aim of this study was to highlight the unique case of an intrathoracic mesothelial cyst in a 5-year-old child that was treated with a thoracoscopic resection.
Background: Mesothelial cysts are benign cysts lined by a single layer of mesothelial cells. These rare lesions can be found on, or adjacent to, serous membranes but are only occasionally located within the thorax. In children, less than 10 intrathoracic cases have been described thus far, most of which are diaphragmatic in origin.
Case: An asymptomatic 5-year-old female presented with a left-sided mediastinal mass incidentally discovered on a chest radiograph during a work-up for scoliosis. Magnetic resonance imaging demonstrated a hypodense, nonenhancing lesion measuring 3 x 2.5 x 8 cm in the left paravertebral region. Video-assisted thoracoscopy was employed for diagnosis and excision. The thin-walled cyst was dissected free from the pleura and completely excised thoracoscopically. Histopathology showed a benign, unilocular cyst lined with a cuboidal mesothelium that stained strongly positive for cytokeratin.
Conclusion: Mediastinal mesothelial cysts have very rarely been reported in the pediatric population. In the case presented, the benign cyst was easily excised by using a minimally invasive thoracoscopic approach. Given the appropriate indications, we feel that thoracoscopic resection is well suited for such cases.