Mediastinal growing teratoma syndrome after cisplatin-based chemotherapy and radiotherapy for intracranial germinoma

Abstract

Nonseminomatous germ cell tumor (NSGCT) has been treated with cisplatin-based chemotherapeutic regimens. In cases of good response of tumor to chemotherapy, elevated tumor markers such as alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG) return to normal with tumor shrinkage. However, a small proportion of cases demonstrate tumor growth during or after the treatment. This distinctive situation was first described for testicular NSGCT by Logothetis and colleagues 1 and was designated the growing teratoma syndrome (GTS). In this report we describe GTS of the mediastinum after cisplatin-based chemotherapy and radiotherapy for intracranial germ cell tumor. Clinical Summary A 20-year-old man with a rapidly growing mediastinal tumor was referred to our department. One month before, tumors in the pineal and the suprasellar regions had been found, with bitemporal hemianopia. Results of routine blood chemistry and coagulation studies were normal; however, serum AFP and hCG were increased to 447 ng/mL and 240 ng/ml, respectively. Serum carcinoembryonic antigen level was normal. The patient underwent partial resection of the suprasellar lesion for pathologic diagnosis. The pathologic diagnosis in the lesion was germinoma. Thereafter, the patient underwent chemotherapy consisting of ifosfamide, cisplatin, and etoposide followed by 20 Gy local irradiation. The intracranial lesions completely disappeared. Serum AFP and hCG were decreased to within normal limits. After these therapies, a chest roentgenogram accidentally disclosed a mass located in the mediastinum. Chest computed tomography showed a round and lobulated mass in the anterosuperior mediastinum. The size of the mass rapidly increased (Figure 1). Tumor doubling time was calculated at 34.3 days. The tumor showed no response to 20 Gy irradiation. Gallium scintigraphy showed a slightly intense mediastinal enhancement region and no other lesion outside the chest. Histologic examination of a percutaneous needle biopsy specimen showed necrotic and fibrous connective tissue. A median sternotomy was performed. The tumor was encapsulated in the thymic tissue. A complete resection was performed with negative margins. On pathologic examination, the specimen of the mediastinal tumor was characteristic of mature teratoma. The tumor consisted of mature squamous epithelium with immature glandular structures. Immature structure tested immunohistochemically positive for carcinoembryonic antigen and keratin but negative for AFP and hCG (Figure 2, A). However, the immature component was less than 10% of the tumor. Retrospective pathologic examination in the intracranial lesion resected before chemoradiotherapy revealed pure germinoma with negative results of immunohistochemical testing for AFP and hCG (Figure 2, B). The postoperative course was uneventful. At 8-month followup, the patient is doing well with no evidence of disease.