Incidentally Diagnosed Mediastinal Mature Teratoma in an Infant: About A Case Report and Literature Review

Mature teratoma accounts for 75% of germ cell tumors of the mediastinum, including 6 to 18% of tumors of the anterior mediastinum in children. The risk of malignancy of this benign tumor is exceptional. Respiratory and cardiac symptoms are its mode of revelation due to the mass effect on the adjacent mediastinal structures. We report the case of a 4-month-old male infant with an anterior mediastinal mass found during a cardiac ultrasound as part of a heart murmur assessment. The rest of the clinical examination was normal. The chest CT scan highlighted an anterior mediastinal mass with a fatty, cystic, and tissue component developed at the expense of the right part of the thymus without compression of adjacent structures. Tumor markers were negative. The lesion was excised by right lateral thoracotomy. The pathological analysis favored a mature teratoma. No complications or recurrences occurred after a 21-month follow-up. Mature thoracic teratoma is a rare benign tumor in the pediatric population. Its diagnosis is most often incidental or evoked in case of chest symptoms. Complete surgical excision of this tumor results in complete healing without risk of recurrence.