Adult Medullary Diffuse Midline Glioma Presenting with Orthostatic Hypotension: A Case Report.

Diffuse midline glioma, H3K27-altered, is a rare and aggressive central nervous system tumor that typically affects children, whereas adult cases are uncommon and less well characterized. We report a 43-year-old woman who experienced progressive lightheadedness for 10 months and was diagnosed with orthostatic hypotension on the basis of a positive tilt-table test result. Despite treatment with midodrine, her symptoms worsened, and dysarthria, dysphagia, sensory disturbance, and gait instability later developed. Magnetic resonance imaging confirmed an intra-axial mass in the dorsal medulla oblongata. Partial resection was performed, and histopathological examination with immunohistochemistry confirmed the diagnosis of H3K27-altered diffuse midline glioma. The patient subsequently received adjuvant chemoradiotherapy. Although her motor function improved postoperatively, severe orthostatic hypotension persisted, leading to recurrent syncopal episodes that significantly hindered rehabilitation. The solitary nucleus in the dorsal medulla plays a central role in the baroreflex by relaying sympathetic and parasympathetic signals within the central autonomic network. Disruption of this network by medullary tumors can impair blood pressure regulation, causing orthostatic hypotension. Although orthostatic hypotension has been reported in association with various medullary tumors, gliomas are rarely implicated. To our knowledge, this is the first reported case of medullary diffuse midline glioma presenting with orthostatic hypotension under the current World Health Organization molecular classification. This case highlights the importance of considering brain magnetic resonance imaging in patients with newly developed or severe orthostatic hypotension, particularly when accompanied by neurological symptoms, to enable timely diagnosis and management.