[Pilomyxoid astrocytoma presenting in an elderly patient: a case report]

A 77-year-old man presented with progressive visual disturbance. MR images revealed a mass lesion mainly spreading in the left basal cistern, sylvian fissure and to the left hypothalamic region, with ventricular enlargement. To obtain precise diagnosis of the mass lesion, an open biopsy was performed. The pathological diagnosis was pilomyxoid astrocytoma (PMA). The patient was discharged without adjuvant therapy. A Ventriculoperitoneal shunt procedure was performed afterwards because his hydrocephalic symptoms progressed. PMA is a rare tumor newly added to the glioma section by the WHO classification renewed in 2007, and generally develops in infancy. To our knowledge, there are only four adult cases being reported. In those cases, the symptoms of the disease developed during the second to fourth decade of life. The onset at a more advanced age as in the present case seems to be extremely rare. The treatment strategy described in infant cases is similar to that for pilocytic astrocytoma, but there are only few reports. To establish a treatment protocol for adult patients, further more cases are needed to accumulate knowledge of this rare brain tumor.