Imaging-tracked progression of primary leptomeningeal gliomatosis: A case report.

Background: Primary leptomeningeal gliomatosis (PLG) is a rare neoplasm characterized by the diffuse spread of glial tumor cells throughout the leptomeninges without any evidence of a primary tumor source in the brain or spinal cord parenchyma. Here, we present a case of PLG potentially linked to prior interventional radiotherapy. Case Description: The patient was a 75-year-old woman with a history of interventional radiology for a left internal carotid cavernous sinus fistula 13 years before presentation. Routine follow-up fluid-attenuated inversion recovery magnetic resonance imaging revealed a high intensity region spreading from the deep white matter of the subventricular zone (SVZ) to the insular cortex and medial temporal lobe. Subsequently, contrast-enhanced T1-weighted imaging revealed an enhanced effect consistent with extensive leptomeninges extending from the basilar cistern to the left Sylvian fissure. The patient underwent surgery, and subsequently histological examination of extracted tissue revealed a glioblastoma (GBM). Despite postoperative concurrent chemoradiotherapy and adjuvant temozolomide chemotherapy, the tumor increased in size, and the patient died 2 months postoperatively. Conclusion: This case highlights the importance of careful follow-up and early therapeutic intervention in PLG, as it can be difficult to diagnose leptomeningeal lesions alone. This case also raises the possibility of radiation-induced GBM, and the criteria for diagnosis were fully met. The progression of PLG from the SVZ to the leptomeningeal site was tracked using imaging, providing valuable insights into the pattern of spread of this rare condition.