Isolated recurrence of intracranial and temporal bone myeloid sarcoma--case report.

A 52-year-old man presented with a rare case of isolated recurrence of myeloid sarcoma (MS) manifesting as rapidly growing intracranial and temporal bone masses 5 years after complete remission (CR) of acute myeloid leukemia (AML) (M2 in the French-American-British classification). Magnetic resonance imaging and computed tomography of the head revealed enhanced mass lesions on the superior aspect of the right petrous bone and within the right mastoid air cells, extending into the right middle ear cavity without bone destruction. Peripheral blood testing found no evidence of relapse. As the right temporal bone mass showed significant growth into the right temporal lobe over one month and diagnostic tissue was not available, he was admitted to our department for biopsy. On admission, blood testing showed relapse of AML and tumoral hemorrhage in the right temporal lobe. Emergent evacuation of the hematoma and biopsy of the right temporal lobe tumor was performed, resulting in a diagnosis of MS. Chromosomal analysis of the peripheral blood identified t(8;21)(q22;q22) abnormality. Before initiation of anti-AML chemotherapy, tumoral bleeding occurred again and he died 12 days after the operation of brain herniation. Autopsy revealed leukemia cell infiltrations in the perivascular region of the peritumoral brain parenchyma associated with hemorrhage, indicating vascular damage caused by leukemic cell infiltration from MS induced cerebral hemorrhage. Although relapse after 5 years of CR is uncommon in patients with AML, the possibility of MS recurrence must be considered.