Neurologic complications of hairy cell leukemia.

Involvement of the nervous system in some forms of leukemia is a common, well-recognized problem. To our knowledge, no study has investigated hairy cell leukemia (HCL) with this question in mind, so we reviewed the records of 108 patients with HCL seen during a seven-year period. Neurologic complications developed in roughly 5% of these patients. Direct infiltration of the nervous system in cases of HCL has rarely been reported in the literature, and the clinico-pathologic appearance is insufficiently documented. We found no cases of direct invasion of the nervous system and only one case of vertebral-body invasion and radicular compression, indicating that epidural spread is also rare. Infection was the most frequent cause of neurologic problems in this series of patients with HCL.