Mediastinal teratoma with double malignant transformation

Abstract

We report a case of a 65-year-old woman with retrosternal discomfort, dyspnea, and weight loss in whom the computed tomography showed a multicystic mass with fat content and calcified wall in the anterior mediastinum. After surgical resection, pathological examination revealed synchronous primary colorectal adenocarcinoma and primary carcinoid tumor arising in a mediastinal mature cystic teratoma. Treatment with oxaliplatin and capecitabine was instituted, and subsequent checkups showed no evidence of recurrence. Malignant transformation of mature cystic teratoma is a rare complication that occurs in 1–3% of these tumors and consists of a nongerm cell malignant tumor arising from a preexisting mature teratoma. Any of the constituent tissues of a teratoma has the potential to undergo malignant transformation. In case of limited disease, treatment should be surgical. There is no consensus regarding adjuvant treatment, and the existence of a double neoplastic lineage may complicate the choice of chemotherapy treatment.