Mediastinal mature teratoma perforating the right lung that was successfully resected with complete thoracoscopic surgery: A case report

INTRODUCTION: A perforating mediastinal mature teratoma can cause severe inflammation and adhesion; therefore, open surgery is usually performed. Asymptomatic perforation involving a teratoma is very rare. Complete thoracoscopic surgery is often difficult because of inflammation associated with perforation and the frequently large size of a mediastinal mature teratoma. We report a rare case of an asymptomatic perforating mediastinal mature teratoma successfully treated with complete thoracoscopic surgery. PRESENTATION OF CASE: The patient was a 15-year-old girl with an abnormal shadow at the mediastinum seen on chest radiography at a health examination performed at her junior high school; an asymptomatic mediastinal tumour was suspected. Enhanced computed tomography revealed a 6.5 × 3.5-cm tumour associated with the right upper lobe. Thoracoscopic surgery was performed using 4 access ports. Although there were inflammatory changes, hemi-thymectomy and right upper lobectomy were achieved with complete thoracoscopic surgery. The tumour included the skin, sebaceous glands, hair, and pancreatic tissue and was diagnosed as a mature teratoma perforating the right upper lobe. DISCUSSION: There might be limited inflammatory changes if the patient has few or no symptoms, as in our case. In such cases, the tumour may be excised even if it is large. CONCLUSION: We report a rare case of an asymptomatic perforating mediastinal mature teratoma that was successfully treated with complete thoracoscopic surgery. Although infection, inflammatory adhesion, large tumour size, and the need for radical cure are concerns, complete thoracoscopic surgery might be helpful. In cases of few or no symptoms, thoracoscopic surgery is worth challenging.