Introduction: Mediastinal Germ cell tumors are rare, and seminomas are less frequent than non-seminomatous tumors. Due to the slow growth of seminomas, most of them have been found large at the time of a diagnosis. In this work, we aimed to study the management peculiarities of primary mediastinal seminoma(PMS).

Methods: Between 1997 and 2022, 3patients were managed for a PMS, with curative intent, in the thoracic surgery department of Abderrahmen Mami hospital, Ariana, in Tunisia. In all patients, gonadal involvement was excluded.

Results: There were 3 men with an average age of 24 years. The main symptom was chest pain. The thoracic CT scan showed a heterogeneous mediastinal mass located in the anterior and superior mediastinum(n=3) compressing the large vessels(n=1). Mean size of the tumors was 7 cm. The tumor markers were negative. Chemotherapy was the first-line treatment. All of them received 3 to 6 cycles of BEP (bleomycin, etoposide and cisplatin). Surgery was indicated in all patients? with remaining tumor mass> 3 cm. The approach was sternotomy. Surgical procedure was tumor resection(n=3), extended to the left brachiocephalic venous trunk, to the right lung, pericardium, and mediastinal fat(n=1).  The postoperative course was uneventful(n=3). Pathology examination concluded to a seminoma, one of which was intra-thymic, completely sterilized by chemotherapy(n=3). Adjuvant radiotherapy was performed afterwards. The average survival was 24 months without recurrence noted.

Conclusion: Seminomas represent a therapeutic multimodal challenge. Because of their rarity, a multidisciplinary approach in a specialized center is necessary, in order to ensure adequate care and a rigorous follow-up.