Abstract
INTRODUCTION: Primary brain sarcoma is extremely rare and has a very poor prognosis. Sarcomas are a highly diverse group, with over 100 different subtypes identified in the recent WHO classification. Case: In this case, we describe a 51-year-old man diagnosed with primary right frontal poorly differentiated sarcoma. He experienced cognitive changes for weeks. Brain MRI revealed a lobulated mass with peripheral enhancement measuring 67 mm by 61 mm by 52 mm. He underwent gross total resection, and pathology indicated high-grade poorly differentiated sarcomatous lesions. Further analysis at Memorial Sloan Kettering and NIH failed to match any DNA methylation class. Next generation sequence (NGS) testing revealed mutation of NF2, CDKN2A, COL3A1, CD33, and PIK3CA genes, increased PD-L1 mRNA, and PD-L1 expression, greater than 50%. The conclusive diagnosis was a PD-L1 high poorly differentiated sarcoma, not otherwise specified. Since no primary site was found elsewhere, planned to treat it as a primary brain sarcoma. Patient underwent focal radiation therapy with a plan to start immunotherapy combination of anti-CTLA4 and anti-PD1 therapy. In addition, an anti-VEGF therapy with pazopanib because of the efficacy of pazopanib in the setting of soft tissue sarcomas. The patient completed IMRT on 07/13/2023 and presented with a new onset of left leg weakness and urinary incontinence on 07/25/2024, further neuraxis imaging with MRI showed local and distant intracranial recurrence with drop metastasis at C1, C5-C6, and S2. The patient was started on IMRT to address drop metastasis, however further clinical decline led to treatment discontinuation. DISCUSSION: There is no consensus on treatment guidelines on primary brain sarcomas given that they are exceedingly rare. DNA methylation and NGS provided very valuable information. We were unable to find any reported cases of primary brain sarcoma with drop metastases and leptomeningeal disease in the literature.