Human echinococcosis is a zoonotic disease caused by accidental ingestion of tapeworm eggs of the genus Echinococcus, shed in the feces of animal definitive host. In the human duodenum, these eggs release oncospheres, which penetrate the intestinal wall and via the bloodstream reach the liver—the most common site for development of cysts. However, it is important to remember that any other organ can be affected via the bloodstream, due to larvae size. In Europe, the most diagnostically relevant species are Echinococcus granulosus, with a median incidence of 0.6 cases per 100,000 inhabitants, and Echinococcus multilocularis, with 0.1 cases per 100,000 inhabitants. This article aims to describe an exceptionally unusual location of human cystic echinococcosis in the anterior mediastinum. We describe the role of multidisciplinary diagnostics in establishing the definitive diagnosis. The pathomorphological examination, radiological imaging and serological testing for diagnosing cystic echinococcosis are hereby described. It is particularly important to avoid reporting unspecified Echinococcus (NOS) if possible, as the management and treatment of patients with echinococcosis varies depending on the species.

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.