Ewing sarcoma extraosseous brain metastasis presenting with an intracranial hemorrhage: illustrative case

Abstract

Background: Ewing sarcoma is a rare malignant tumor that primarily affects children and young adults, commonly metastasizing to the lungs, bone, and bone marrow. CNS involvement is extremely rare, especially with the primary presentation of intracranial hemorrhage. Current protocols do not include routine neuroimaging, potentially delaying the detection of brain metastasis. Additionally, Ewing sarcoma patients are at risk of developing chemotherapy-induced thrombocytopenia that can significantly increase the possibility of intracranial hemorrhage.

Observations: A 19-year-old male with metastatic Ewing sarcoma of the pelvis presented with sudden-onset severe headache, seizures, and unresponsiveness. Imaging revealed a large left frontoparietal intraparenchymal hemorrhage with midline shift requiring emergency surgical decompression. Histopathology confirmed metastatic Ewing sarcoma. Despite proper management, the patient's medical condition deteriorated, leading to subsequent death.

Lessons: Early and interval brain imaging should be considered in patients diagnosed with Ewing sarcoma, especially those undergoing chemotherapy with thrombocytopenic effects. Earlier detection of CNS involvement may facilitate timely intervention and improve outcomes. Future research should explore optimized surveillance strategies and the connection between metastatic intracranial Ewing sarcoma and the unusual presentation of hemorrhage. https://thejns.org/doi/10.3171/CASE25246.

Keywords: Ewing sarcoma; brain metastasis; case report; intracranial hemorrhage.

FIG. 1.

Noncontrast CT scans of the head on initial presentation to the emergency department. Cross sections in the sagittal (A), coronal (B), and axial (C) planes revealed a large left frontoparietal intraparenchymal hemorrhage measuring 6.7 × 5.9 cm with intraventricular extension, 1.3 cm of left to right midline shift, and left uncal herniation.

FIG. 2.

Histopathological analysis of intraoperative tissue specimen confirming metastatic Ewing sarcoma. A: CD99 immunohistochemical staining at ×200 magnification revealing a strong and diffuse membranous staining of tumor cells. B: FLI-1 immunohistochemical staining at ×200 magnification positive for strong nuclear immunoreactivity on biopsied tumor cells. C: NKX2.2 immunohistochemical staining at ×200 magnification demonstrating diffuse nuclear positivity of tumor cells. D: H&E staining at ×400 magnification revealing characteristic small, round, and uniform blue cells with a high nuclear-to-cytoplasmic ratio, typical for Ewing sarcoma neoplasms.

FIG. 3.

Noncontrast CT scans of the head on POD 1 following decompressive craniectomy and EVD placement. Postoperative changes consistent with intracranial pneumocephalus, vasogenic edema, EVD placement, persistent left lateral intraventricular hemorrhage, and small areas of hemorrhagic foci are seen on the sagittal (A), coronal (B), and axial (C) cross sections.

FIG. 4.

Noncontrast CT scans of the head on POD 11. Cross sections in the sagittal (A), coronal (B), and axial (C) planes demonstrate a mild degree of improvement of vasogenic edema, asymmetric lateral ventricles with no or minimal evidence of blood products present within the ventricles without hydrocephalus, and no midline shift.