Intracranial Myeloid Sarcoma Arising Intra-axially From Acute Myeloid Leukemia: A Case Report and Literature Review.

Intracranial myeloid sarcoma is a rare brain tumor and an extramedullary manifestation of malignant hematopoietic neoplasms of myeloid origin. A 76-year-old right-handed male patient was initially diagnosed with acute myeloid leukemia (AML; M4Eo). Three years later, the patient experienced headaches, dizziness, nausea, and gait disturbances. Magnetic resonance imaging of the head revealed a mass lesion that appeared to be extra-axial in the right cerebellum with well-defined borders that did not show contrast enhancement and was in contact with the dura mater. The patient underwent surgical tumor resection using the lateral suboccipital approach. The tumor did not attach to the dura mater, indicating susceptibility of an intra-axial tumor. Complete tumor resection was performed. The intraoperative pathological diagnosis revealed the involvement of AML characterized by small round cells diffusely increasing in size with angiogenesis and invasion of macrophages. In conclusion, we present a rare case of intracranial myeloid sarcoma arising intra-axially and originating from an AML that was treated with surgical tumor resection. Although it is difficult to determine whether the tumor was extra-axial or intra-axial on imaging, intracranial myeloid sarcoma should be considered as a differential disease when the patient has a history of hematological neoplasia, such as AML.