Paradoxical response of a pineal immature teratoma to combination chemotherapy.

A case of primary intracranial germ cell tumour is reported in a 5-year-old Chinese boy who presented with symptoms and signs of increased intracranial pressure. Computed tomography (CT) scan of the brain revealed a multicystic tumour over the pineal region. Stereotactic biopsy yielded enteric epithelium and isolated cells with hyperchromatic nuclei and high nuclear-to-cytoplasmic ratio, suggesting the diagnosis of an immature teratoma. Grossly elevated serum and cerebrospinal fluid (CSF) levels of alpha-fetoprotein and mildly elevated levels of beta human chorionic gonadotrophin suggested the simultaneous presence of embryonal tissues. Combination chemotherapy with cisplatin, etoposide, and bleomycin resulted in a gradual but complete normalisation of the serum and CSF tumour markers. Paradoxically, the patient's consciousness deteriorated and repeat CT scan after 3 months of treatment showed that the tumour was actually increasing in size. Complete surgical removal was attempted and histologic sections of the specimen revealed only mature teratomatous tissues. The child is now well and remains disease-free with minimal left hemiparesis 12 months after completion of treatment. This case illustrates the importance of combined neoadjuvant chemotherapy and surgery in the management of intracranial non-germinomatous germ cell tumour harbouring both germ cell and teratomatous components, while monitoring of both biochemical and radiological parameters are necessary in assessing the clinical behaviour of mixed germ cell tumours.