Occipital pilomyxoid astrocytoma in a 14-year-old girl--case report.

Pilomyxoid astrocytoma is a recently described tumor. Its most typical morphological characteristics are an angiocentric astrocytic proliferation embedded in a myxoid background. The behavior seems to be unfavorable due to the reported high rate of local recurrence. The earlier studies indicated that pilomyxoid astrocytoma typically affects young children and arises in the hypothalamic/chiasmatic region. We report a case of a 14-year-old patient with a 6-year history of absence seizure. Magnetic resonance imaging showed a right occipital lesion of approximately 3 cm in diameter. The patient underwent the surgical procedure with gross total excision. Histologically, the tumor was mainly composed of a monomorphous population of bipolar elongated piloid cells radially arranged around thin-walled blood vessels in a prominent myxoid background. There were focal hemorrhagic foci but no bona fide evidence of tumor necrosis or mitoses. Rosenthal fibers and eosinophilic granular bodies were not observed. The postoperative course was uneventful. No adjuvant therapy was administered. The patient is alive and well at 18-month follow-up. The case presented provides evidence that pilomyxoid astrocytoma can occur at a later age and can arise in regions different from hypothalamic/chiasmatic.