Distinctive pleomorphic xanthoastrocytoma-like tumor with exclusive abortive or aberrant neuronal differentiation and repeated recurrence--case report.

A 9-year-old girl with a 1-month history of generalized seizure presented with a distinctive tumor resembling pleomorphic xanthoastrocytoma. Neuroimagings showed a right frontotemporal lobe tumor. Histological examination of the resected tumor indicated similarity to pleomorphic xanthoastrocytoma without staining for glial fibrillary acidic protein. The neuronal immunoreactivity and ultrastructural features showed two discrepancies: Numerous cytoplasmic processes containing rich structures suspected to be microtubules and neurofilaments were present, but neurofilament protein 70 kd/200 kd staining was negative; and many tumor cells showed synaptophysin staining, but no synaptic structures or vesicles were observed. She suffered recurrence 14 months after the first surgery. The specimen from the second operation revealed no malignant transformation with a MIB-1 labeling index of 1.9%. Only 2 months after the second operation, there was a second recurrence. Irradiation was administered (60.2 Gy). Twenty-eight months later, no tumor progression was seen. This tumor was an unconventional type with "abortive" or "aberrant" neuronal differentiation or an extreme variant of pleomorphic xanthoastrocytoma.