Rapidly growing anterior mediastinal teratoma in a young adult female: successful resection via robotic-assisted thoracoscopic surgery.

Introduction: Mediastinal teratomas are rare, typically benign germ cell tumors that are often discovered incidentally due to their slow growth and asymptomatic nature. Presentation of the Case: We present this unusual case of a 22-year-old woman who presented with retrosternal chest discomfort, and was incidentally found to have a large anterior mediastinal mass measuring 8 × 8 × 5 cm on computed tomography (CT) scan. Imaging characteristics - including fat and calcification - were consistent with a mature cystic teratoma. Notably, a CT scan performed 4 years earlier was completely normal, suggesting unusually rapid tumor growth. The patient underwent robotic-assisted thoracoscopic surgery (RATS) for resection of the mass. Intraoperatively, the lesion was found to be cystic and adherent to the pericardium and closely associated with the right phrenic nerve, without clear evidence of invasion. The procedure was completed successfully, with an uneventful postoperative recovery. Histopathologic analysis confirmed a mature teratoma without malignant features. Discussion: Although mediastinal teratomas are classically indolent, this rare case illustrates that they may occasionally demonstrate rapid growth and present unexpectedly. Timely imaging and intervention are crucial in such scenarios. The anatomical complexity of the mediastinum presents surgical challenges, especially in large masses. Conclusion: This case highlights the potential for rapid growth in mediastinal teratomas and supports the feasibility and safety of RATS as a minimally invasive approach. This technique enables excellent exposure and precise dissection in anatomically complex regions, with favorable patient outcomes.