Isolated recurrence of acute myeloid leukemia in the cerebellum: illustrative case.

backgroundMyeloid sarcoma is a rare malignant hematopoietic neoplasm that arises at extramedullary sites. Although myeloid sarcoma may involve any organ, central nervous system (CNS) involvement is exceptionally rare. To date, few case reports and case series have described CNS myeloid sarcoma, the majority of which include peripheral disease. OBSERVATIONS: The authors present an illustrative case of an adult male with acute myeloid leukemia (AML) in remission relapsing with an isolated, diffuse myeloid sarcoma of the cerebellum. Magnetic resonance imaging showed posterior fossa crowding and diffuse enhancement within the cerebellar white matter without an apparent mass lesion. The patient required ventriculostomy due to obstructive hydrocephalus and ultimately suboccipital craniectomy with duraplasty due to posterior fossa compression. An open cerebellar biopsy revealed myeloid sarcoma. Peripheral studies did not meet the criteria for recurrent AML. The patient subsequently received high-dose systemic chemotherapy and has responded well to treatment. LESSONS: Myeloid sarcoma may be a neurosurgical lesion because it has the potential to cause mass effect with obstructive hydrocephalus requiring emergent cerebrospinal fluid diversion and possible decompression. The authors report a rare case of isolated recurrence of AML in the form of diffuse CNS myeloid sarcoma and describe the role of neurosurgery in its diagnosis and treatment.