Teratoma is a tumor originating from reproductive cells. They are mostly localized in gonads, in the mediastinum, it constitutes about 15% of tumors in this area. It is usually diagnosed incidentally, mostly among young adults. The authors describe the case of a young woman with the detected tumor in the

anterior mediastinum. She has an operation of parasternal mediastinotomy, during which, the fragments of the tumor were collected. In the perioperative period, the fistula along the wound has developed, joining the light of a tumor with the reservoir in the soft tissues of a chest wall. The punctures of this reservoir and the release of a liquid produced by the secretory tissues of a tumor were necessary for the patient.

From the collected fragments a full-grown teratoma has been identified and finally the anterior mediastinum has been removed. After the removal of the teratoma there were no further complications.