Thoracic benign cystic mesothelioma.

Background: Benign cystic mesotheliomas (BCMs), also known as multilocular mesothelial inclusion cysts, inflammatory inclusion cysts or multicystic mesothelial proliferation, are frequently observed in females and are localised localised in the pelvic peritoneum. They are rarely present in the thoracic and mediastinal areas; however, these locations have been reported in a few cases in the literature.

Case Presentation: We present the case of a woman with an intrathoracic BCM. A 28-year-old female patient presented with a cystic mass of 8 × 6 × 6 cm in the left hemithorax shown by computed tomography of the thorax. The patient underwent cystic mass excision with video-assisted thoracoscopic surgery (VATS), which was completed without complications. The diagnosis was confirmed histopathologically after the surgical resection.

Conclusions: Due to BCMs' non-specific clinical symptoms and radiological imaging, preoperative diagnosis is difficult, and they are often confused with pericardial cysts. There is no standard treatment protocol; however, VATS and en bloc resection are the most frequently used treatment options for mediastinal localization. Since these lesions slow proliferation rates have the potential for local recurrence and low malignant transformation, close follow-up is recommended. In this case report, we aimed to present a rare BCM case with intrathoracic paracardiac localization was completely excised through VATS. No recurrence has been detected in three years of follow-up.