NCMP-02. BIOPSY OUTCOMES OF PATIENTS WITH SUSPECTED LEPTOMENINGEAL CARCINOMATOSIS: A RETROSPECTIVE CASE SERIES

Abstract

Abstract BACKGROUND Leptomeningeal carcinomatosis is commonly considered when patients present with meningeal enhancement on magnetic resonance imaging (MRI), even without a known primary malignancy. In practice, some clinicians advocate for early meningeal biopsy to expedite diagnosis, citing lack of specificity of other testing, such as cerebrospinal fluid (CSF) analysis. METHODS We identified a cohort of patients with meningeal enhancement that underwent biopsy for diagnostic purposes between 2010 and 2022. Presenting symptoms, physical exam, enhancement pattern on MRI, other imaging findings, CSF parameters, other laboratory results, final diagnosis, and recommended treatment were recorded when available. RESULTS Out of nearly 100 cases included, the majority were autoimmune or inflammatory in etiology. Only 13 patients were diagnosed with malignancy-related enhancement, and 10 of these cases were felt to be true carcinomatosis. Nine out of the 13 patients were diagnosed with lymphoma. Four of these lymphomas were diagnosed on systemic biopsy, with meningeal biopsies negative for malignant cells. The other malignancies included systemic adenocarcinoma, oligodendroglioma, and a rare hematologic cancer. Nearly all 13 patients had abnormal CSF parameters, notably pleocytosis, but none had malignant cells in the fluid. Most frequent presenting symptoms were encephalopathy, vision changes, and strength/sensory changes. MRI often showed cranial nerve or general cerebral and cerebellar involvement, and physical exam often showed cranial nerve, strength, and sensory deficits. All patients proceeded with chemotherapy after diagnosis. CONCLUSIONS When leptomeningeal carcinomatosis is considered based on MRI enhancement, the clinical approach should continue to revolve around indirect testing such as CSF analysis, serum studies, and other imaging techniques to consider alternative biopsy sites before pursuing direct sampling with meningeal biopsy. With this approach, many patients with suspected carcinomatosis can avoid undergoing meningeal biopsy and decrease the chance of treatment delay.