[Thymoma in children: a report of one case]

Thymoma is an uncommon tumor of childhood. It is an anterior mediastinal tumor with few symptoms. The pleura is the most frequent metastatic site. Surgery is the treatment of choice and the most important prognostic factors are the stage at initial presentation and whether complete resection can be performed.

A 6-year-old girl with no pathological antecedent presented with a history of prolonged fever. Frontal chest radiography showed a large mediastinal soft tissue mass with sharp lateral and inferior margins. Computed tomography showed a large anterosuperior and medium mediastinal mass measuring 83 mm × 70 mm, associated with variable size mediastinal adenopathy, suggesting the diagnosis of lymphoma. Histological examination of bone marrow biopsy found no haematological malignant diseases such as lymphoma. The histological examination of computed tomography (CT)-guided transthoracic biopsy demonstrated proliferation of polyclonal lymphocyte T cells, confirming the diagnosis of thymoma. The patient benefited from induction chemotherapy (cisplatin and VP16) followed by surgery with complete resection. The patient is doing well 24 months after resection and has no signs of recurrence; CT follow-up showed a stable size of residual thymus.

Thymoma is a benign tumor but the significant risk of recurrence warrants long follow-up.