Myeloid sarcoma of the brain. A case report

We report a case of myeloid sarcoma of the brain mimicking a meningioma on CT scan. The lesion was first morphologically misdiagnosed as a lymphoma, but correctly identified by using immunochemistry with anti-myeloperoxidase, anti-CD68, anti-CD15 antibodies. An acute myeloid leukemia was diagnosed 5 months later. Myeloid sarcoma is frequently mistaken for malignant lymphoma, especially when it presents without leukemic manifestation, even at immunohistochemistry, since both express some leukocyte antigens. Careful evaluation of morphology for evidence of myeloid differentiation, and immunohistochemistry using anti-myeloperoxidase, anti-lysozyme, CD15, CD68 antibodies, should be used to confirm the diagnosis and to rule out lymphoma since the treatment is different.