A Rare Case of Intracranial Myeloid Sarcoma

A 65-year-old male was admitted to the hospital in August 2024 with a headache accompanied by vomiting for 2 days and fever for 1 day. The patient was diagnosed with acute myeloid leukemia 2 years ago. After admission, the patient’s white blood cell count was 2.22 × 109/L, neutrophil count 1.57 × 109/L, lymphocyte count 0.55 × 109/L, red blood cells 3.7 × 10/12 L, hemoglobin level 80 g/L, and platelet count 44 × 109/L. Bone marrow aspiration showed active granulocyte and erythroid cell proliferation with a decreased platelet count. Flow cytometric immunofluorescence analysis showed that no original or naive myeloid cells with obvious immunophenotypic abnormalities were detected by FCM. CT of the brain revealed a hyperdense mass in the left temporal lobe with peripheral edema [Figure 1a]. On MRI, the mass was hypointense on T1WI and slightly hyperintense on T2WI [Figure 1b and c], the DWI shows restricted diffusion at the peripheral [Figure 1d], with post-contrast images showing significant peripheral contrast enhancement [Figure 1e]. Additionally, it is worth noting that the MRI of the patient’s brain from 3 months ago showed no significant abnormalities. The pathological findings confirmed myeloid sarcoma (MS).Figure 1: Non-enhanced brain CT images demonstrate a hyperdense mass in the left temporal lobe with surrounding edema (a). Brain MRI in T1-weighted images shows the mass as hypointense and slightly hyperintense on T2-weighted images (b, c), The DWI shows restricted diffusion at the peripheral (d). Post-contrast images show significant peripheral contrast enhancement (e)MS is an uncommon malignant tumor, also known as granulocytic sarcoma or chloroma. MS of the central nervous system is a rare manifestation of acute myeloid leukemia, chronic myeloid leukemia, and other myeloproliferative diseases.[1] MS can occur anywhere in the body and is composed of immature myeloid cells, most commonly in the bones, skin, or lymph nodes,[2] but is rare in the brain. There are three types of myeloid sarcoma as follows: i) granulocytic sarcoma, ii) monoblastic sarcoma, and iii) the rarer type of neoplasm that consists of three lineages of hematopoietic cells or blasts, and is usually associated with chronic bone marrow proliferative diseases. Granulocytic sarcoma is the most common.[3] Due to the rarity of intracranial MS, it often leads to misdiagnosis. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patients understand that their name and initials will not be published, and due efforts will be made to conceal their identity; however, anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.