Clinical presentations, diagnosis and management of primary mediastinal cysts: A retrospective study

Introduction: Primary Cystic lesions of mediastinum are usually seen in the three compartments of mediastinum, and they may arise from any organ in the mediastinum. The most of these cystic lesions are benign and may be asymptoms. But large cysts may produce symptoms related to compression of adjacent structures. The two most common histological variants of PMCs are bronchogenic and thymic cysts. CXR, Computed tomography and magnetic resonance are routinely used for diagnosis of these lesions. Although computed tomography offers superior than others, magnetic resonance is useful in differentiating cysts that contain watery material from solid component. Cysts lesion may arise from solid lesions, such as thymoma or teratoma. Primary cystic lesion may arise in three compartments of anterior, middle and posterior mediastinum. In this paper we want to show our experience the clinical presentations’, diagnosis, management and complications after treatment of PMCs

Methods: The medical records of all patients with PMCs, who underwent surgical resection from April 2014 to July 2022, were reviewed and 68 patients were included. Clinical characteristics, imaging features, and surgical approach and outcomes were analyzed. Follow-up data were successfully obtained from 58 of PMCs patients by telephone or in the thoracic clinic every six month. The latest follow-up was October 2023.

Results: The 40 of patients were mail and 28 were female. the age of age of patients were between 10 to 58 years, the tools of diagnosis were CXR, CT –scan and MRI. The approaches for resection were AT, PL thoracotomy and median sternotomy. The mean operation time were 120 ± 58 minutes and intraoperative bleeding were and 324 ± 108 mL. The intraoperative complications rates were in eight pations and 12 postoperative. Seven patients with bronchogenic and four thymus cysts showed severe cyst adhesion to vital mediastinal structures and partial resection was performed. Our analysis shows that a maximal cyst diameter greater than 10 cm was associated with increased risks of operation time, intraoperative blood loss and phrenic nerve or great vessels damages. A total of 58 patients had follow-up data. The median follow-up time was 70 months (range 24 to 72 months). recurrence was not occurred.

Conclusions: CT-scan is best imaging for diagnosis. Location of cysts are important in guiding for a differential diagnosis. Although the content of most these cysts is simple fluid, Furthermore, the presence of solid component may suggest cystic degeneration or cystic component of a solid neoplasm. Surgical resection with thoracotomy is recommended in our situation and the results are acceptable but in recent years, VATS recommended for primary therapeutic strategy in PMCs. Cysts with a maximum diameter greater than ten cm or cysts adjacent to vital mediastinal structures can increase the surgical difficulties and complications.