Objective:

To report a rare case of isolated intracranial myeloid sarcoma (MS) as an extramedullary relapse of acute myeloid leukemia (AML) and review existing literature.

Approach:

• Case Presentation: A 61-year-old female with a history of FLT3-ITD mutated AML presented with cognitive decline. MRI showed a left frontal mass, initially suggestive of meningioma. Histopathological examination confirmed MS.

Key Findings:

• Intracranial MS can occur as an extramedullary relapse in AML patients even after long-term remission, as demonstrated in this case.
• Radiological features of MS, such as restricted diffusion on DWI and significant peritumoral edema, can closely mimic those of meningioma, complicating diagnosis.
• Histopathological and immunohistochemical analysis, revealing immature myeloid cells and specific markers, is essential for definitive diagnosis.

Interpretation:

This case highlights the diagnostic challenges posed by isolated intracranial MS in patients with a history of AML.

Limitations:

• The rarity of isolated intracranial MS makes it difficult to establish comprehensive epidemiological data.
• Standard CNS prophylaxis may not fully prevent extramedullary relapse.

Conclusion:

Timely consideration of MS in the differential diagnosis of new intracranial masses in AML patients is crucial for appropriate treatment.