Introduction: Residual radiologically progressive masses following multimodality treatment of malignant mixed intracranial germ cell tumors are described. Often these enlarge, and this is called the growing teratoma syndrome. A similar phenomenon during radiotherapy alone has not been described.
Subjects and methods: A 5-year old boy presented with features of raised intracranial pressure. Imaging revealed a posterior third ventricular mass, which was biopsied endoscopically.
Results: A review of the scanty tissue was suggestive of a pineal parenchymal tumor, and hence radiation was planned. After just ten fractions, he developed rapid neurological deterioration. Repeat imaging raised a possibility of a teratomatous tumor. He underwent emergency excision. However, he had a stormy postoperative course and succumbed to deep venous infarction. Histology revealed a purely mature teratoma.
Conclusion: Though a growing teratoma syndrome has been described following chemotherapy, no such report while on radiation exists. Ours could be the first such reported case. We discuss the possible mechanisms with a review of the literature.