Primary mediastinal yolk sac tumor with pulmonary involvement in a young adult: a case report

Abstract

Yolk sac tumors (YSTs), also known as endodermal sinus tumors, are rare and highly aggressive malignant germ cell neoplasms that typically arise in the gonads, but may also develop in extragonadal midline locations, such as the anterior mediastinum. In these atypical sites, they predominantly affect young males and often present with nonspecific symptoms, including chest pain, dyspnea, and fever. Mediastinal germ cell tumors account for 10-20% of mediastinal neoplasms and are classified into sem- inomatous and non-seminomatous subtypes, with YSTs belonging to the latter group. Their rapid growth and invasive nature frequently preclude immediate surgical intervention, necessitating a multimodal therapeutic approach. We report the case of a 32-year-old previously healthy man presenting with a two-month history of fever, precordial pain radiating to the left upper limb, and exertional dyspnea. Imaging revealed a large anterior mediastinal mass, and percutaneous biopsy with histopathological and immunohistochemical analysis confirmed the diagnosis of yolk sac tumor. The patient underwent four cycles of neoadjuvant BEP chemotherapy (bleomycin, etoposide, cisplatin), resulting in partial tu­mor regression and identification of a cavitated pulmonary nodule. He subsequently underwent surgical resection via median sternotomy, including excision of the mediastinal mass, pulmonary segmentectomy, and thymectomy, with tumor-free surgical margins. The postoperative course was uneventful, and the patient remains in remission under regular follow-up. This case highlights the importance of early diagnosis, individualized treatmentplanning, and a multimodal approach -combining chemotherapy and complete surgical resection-for effective management of mediastinal YSTs. Long-term surveillance is essential to reduce recurrence and improve overall prognosis.