Isolated Intracranial Relapse of Acute Myelocytic Leukemia (AML) Following 4 and 1/2 Years of Complete Remission

A seven year old Hispanic girl developed headache, backache and vomiting. A computed tomography showed 2 intracranial masses. A complete blood count was normal. Bone marrow aspiration showed hypoplastic but otherwise normal marrow. However, cerebrospinal fluid contained leukemic myeloblasts. Four and a half years earlier the patient had presented with an orbital mass, lethargy, and loss of appetite. MRI demonstrated a mass in left maxillary sinus extending to the left orbital cavity causing left proptosis. Bone marrow aspiration was diagnostic of Acute Myelogenous Leukemia (AML). She was treated with the standard AML chemotherapy regimen. Patient achieved complete remission and remained in remission during the subsequent 4 and a half years until the above event. AML recurrence after 4 years of remission is rare. In addition this patient initially showed the recurrence only in the extramedullary site which is also unusual. We postulate that the intracranial recurrence was due to late activation of latent leukemic cells that had seeded in the leptomeningeal space at the time of original presentation. Because of these 2 unusual aspects we wish to report this case.