Rare Posterior Mediastinal Müllerian Cyst Resected by VATS: Case Report and Literature Review

Background: Müllerian cysts of the posterior mediastinum are exceedingly rare benign lesions that closely resemble other mediastinal cysts on imaging, making preoperative diagnosis difficult. Methods: Here, we report the case of a 36-year-old woman in whom a paravertebral cystic lesion at the T8 level was incidentally detected during evaluation of nonspecific pain in the right upper limb. Laboratory tests and chest computed tomography were unremarkable apart from the well-circumscribed homogeneous mediastinal cyst. The lesion was completely excised via video-assisted thoracoscopic resection. Results: Histopathological and immunohistochemical evaluation confirmed Müllerian differentiation. The postoperative course was uneventful, and no recurrence was observed during 10 months of follow-up. Conclusions: This case highlights the importance of considering Müllerian cysts in the differential diagnosis of posterior mediastinal lesions and demonstrates that complete resection is both diagnostic and curative. A review of the currently available literature offers up-to-date diagnostic and therapeutic approaches for these exceptionally rare lesions.