Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 57 9 2020 04 20 569 571 Ahmet Mesrur Halefoglu Sisli Hamidiye Etfal Training and Research Hospital, University of Health Sciences, Istanbul, Turkey. Betul Duran Ozel Sisli Hamidiye Etfal Training and Research Hospital, University of Health Sciences, Istanbul, Turkey. 2019 02 02 2019 10 31 Pilomyxoid astrocytoma (PMA) is a recently described histological type of pilocytic astrocytoma (PA), but the tumors show histological differences. PMA has more aggressive malignant behavior than PA. Magnetic Resonance Imaging (MRI) may play a crucial role in the preoperative setting and also help to establish an appropriate therapeutic regimen. In this case report, we illustrated MRI findings of a hypothalamic-chiasmatic PMA in a 15-year-old female patient presenting with extensive leptomeningeal seeding. The patient was operated for total tumor resection, but could not survive the second post-operative day. We have comprehensively discussed the clinical, imaging, and histopathological features of these relatively rare tumors and also reviewed the recent literature. https://acta.tums.ac.ir/index.php/acta/article/view/7737