Abstract Details

Title Utilization of Liquid Biopsy in Diagnosis of Leptomeningeal Disease

Topic Neuro-oncology

Presentation(s) P2 - Poster Session 2 (11:45 AM-12:45 PM)

Poster/Presentation
Number 6-002

Objective OBJECTIVE: To illustrate the clinical utility of cerebrospinal fluid (CSF) based liquid biopsy techniques in the diagnosis and management of leptomeningeal disease (LMD) in two distinct challenging cases.

Background BACKGROUND: Leptomeningeal disease (LMD) is a devastating complication of metastatic cancer, affecting approximately 15% of patients with metastatic solid tumors and associated with poor prognosis. Accurate and timely diagnosis is essential to ensure appropriate treatment and optimize quality of life. Although most cases occur in patients with known widespread disease, LMD may occasionally be the initial manifestation of malignancy, presenting significant diagnostic challenges when tissue biopsy is difficult or delayed. Liquid biopsy approaches using CSF can detect tumor cells, cell-free DNA, RNA, and protein biomarkers, providing valuable diagnostic and prognostic data.

Design/Methods DESIGN: Case reports of two distinct cases with respective diagnostic and treatment implications.

Results RESULTS: Case 1: A 56-year-old woman with no previously identified malignancy underwent MRI demonstrating leptomeningeal enhancement involving cranial nerves, brainstem and spinal cord; hydrocephalus developed with disease progression. CSF demonstrated 0.6 nucleated cells, protein 34 mg/dL, and glucose 6 mg/dL; cytology was negative. Empiric antifungal treatment was initiated. Menarini liquid biopsy ultimately demonstrated findings of solid tumor DNA with high tumor burden; subsequent biopsy confirmed histiocytic sarcoma. Case 2: A 31-year-old man with nasal rhabdosarcoma underwent brain MRI demonstrating leptomeningeal disease and hydrocephalus. CSF demonstrated 2.8 nucleated cells, and normal glucose and protein; cytology/flow cytometry showed very rare, atypical cells. Liquid biopsy/ctDNA testing confirmed leptomeningeal spread and additionally identified mutations that allowed for expedited selection of targeted treatment noting setting of uncommon tumor.

Conclusions CONCLUSION: These cases demonstrate how CSF liquid biopsy is a promising adjunct in the diagnosis and management of leptomeningeal disease, particularly when cytology/flow cytometry is non-diagnostic, conventional tissue diagnosis is not readily feasible, and/or rapid molecular insights are required.

Authors/Disclosures
Onilia Zorio, DO (Mayo Clinic) PRESENTER	Dr. Zorio has nothing to disclose.
Brenna C. Beezhold	Ms. Beezhold has nothing to disclose.
Marie F. Grill, MD (Mayo Clinic)	Dr. Grill has nothing to disclose.
Molly Knox, MD	Dr. Knox has nothing to disclose.
Maciej M. Mrugala, MD, PhD, MPH, FAAN (Mayo Clinic)	Dr. Mrugala has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Veevo Biomedicines Inc. Dr. Mrugala has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Arbor Pharmaceuticals. Dr. Mrugala has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Astra-Zeneca. Dr. Mrugala has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Servier. Dr. Mrugala has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Medscape. Dr. Mrugala has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Merck. Dr. Mrugala has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Kyiatec . The institution of Dr. Mrugala has received research support from Arbor Pharmaceuticals. Dr. Mrugala has a non-compensated relationship as a Program Director with Society for Neuro-Oncology that is relevant to AAN interests or activities.

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