Introduction: A pilomyxoid astrocytoma is a rare type of brain tumor that primarily affects young children, typically arising in the hypothalamic-suprasellar region of the brain. Unlike pilocytic astrocytoma, PMA is characterized by a more aggressive clinical course and distinct histopathological features, including a monomorphic cell population, angiocentric arrangement, and a myxoid background.
Case presentation: A 17 months old patient with a history of twin to twin transfusion was brought to the hospital with a complaint of motor regression, compared to his twin. The CT and MRI images revealed an intradural intramedullary spinal mass. The mass tissue biopsy was sent to pathology.
Results: The smear preparation and tissue sections of the mass showed a hypercellular tumor consist of monomorphic bipolar cells with a fibrillary background. Occasionally perivascular proliferation and myxoid material was seen. The tumor cells were diffusely positive with GFAP, highlighting the pyloric process and rare perivascular pseudorosettes. Neurofilament highlighted the entrapped axons in some but not all fragments of tumor. Sox-10 was diffusely positive, synaptophysin was weakly patchy positive in tumor cells. NGS panel showed duplication involving FGFR1. With these morphologic, immunohistochemical and molecular findings, the tumor is diagnosed as ‘Low-grade glioma, most suggestive of pilomyxoid astrocytoma’.
Discussion: Pilomyxoid astrocytoma is recognized as a variant of pilocytic astrocytoma with distinct clinical and histopathological features, typically presenting in younger patients. The treatment strategy, often involving a combination of surgery, chemotherapy, and, in some cases, radiotherapy, must be carefully considered given the tumor's location and the patient's age.