Giant Mediastinal Teratoma in a Child: A Case Report With a Brief Review of the Literature.

Giant mediastinal teratomas in the pediatric population are uncommon entities that may grow insidiously and cause significant compression of intrathoracic structures. We report the case of a 10-year-old girl with a two-year history of progressive exertional dyspnea, chest pain, orthopnea, and increasing thoracic enlargement. Chest radiography demonstrated marked mediastinal widening, and contrast-enhanced chest CT revealed a predominantly cystic mediastinal mass measuring approximately 15 × 14 cm, with mediastinal shift and ipsilateral lung collapse. Routine laboratory tests were within normal limits, and surgical resection confirmed a mature mediastinal teratoma. The patient had an uneventful postoperative course, and follow-up CT showed complete pulmonary re-expansion with no residual lesion. This case highlights the clinical and imaging features that should raise suspicion for a giant mediastinal teratoma in children and underscores the importance of reporting these cases given the limited pediatric literature available.