Thymomas are rare tumors of the anterior superior mediastinum, accounting for about 15% of all mediastinal masses. Although thymomas are histologically benign and grow indolently, some invade the surrounding structures and behave as malignant tumors. Only 40% of thymomas are completely encapsulated, with no evidence of microscopic invasion. Traditional management of invasive thymomas generally involves surgical resection and radiotherapy, but recently cytotoxic chemotherapy, particularly regimens using cisplatin, doxorubicin (Adriamycin), and cyclophosphamide (РАС), has been shown to produce response rates of 70 to 91.8%. In addition to being relatively sensitive to chemotherapy, it appears that invasive thymomas are somewhat indolent with some incurable patients surviving for years. Therefore, some patients who initially responded to chemotherapy will be candidates for salvage chemotherapy.
This is a report of two patients with unresectable invasive thymoma who initially responded to a course of a platinum compound, РАС, and whose recurrence again responded to.
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A 26-year-old Asian man was first seen at our institution in November 1978 with a diagnosis of myasthenia gravis requiring therapy with prednisone and subsequently a thymectomy in December 2008. During the next decade, he suffered recurrent upper respi-ratoiy tract infections and myasthenic exacerbations. He was readmitted to this hospital in May of 1992 for productive cough and fever. A chest radiograph done at this time showed an anterior mediastinal mass, and a subsequent CHN scan confirmed the presence of recurrent mediastinal thymoma with pleural metastasis which was later confirmed by mediastinoscopy and biopsy.
In late May, an open thoracotomy was performed, which showed tumor involvement of the parietal pleura and both vagus and phrenic nerves, precluding complete resection of the tumor. The patient was therefore offered and agreed to treatment with chemotherapy consisting of four courses (every 21 days) of a combination of carboplatin at 300 mg/m2, doxorubicin at 50 mg/m2, and cyclophosphamide at 500 mg/m2 beginning on July 6, 2013.