Infiltrative polyneuropathy due to acute monoblastic leukemia in hematologic remission

A 66-year-old man with acute monoblastic leukemia developed acute polyneuropathy with quadriplegia, autonomic instability, and respiratory failure while he was in hematologic remission following both systemic and intrathecal chemotherapy. Autopsy revealed dense infiltration of somatic and autonomic peripheral nerves, sparing the meninges. There was a small peripheral infiltrate in one of four dorsal root ganglia, but, otherwise, sensory and autonomic ganglia were normal. The blood-nerve barrier may allow some malignant cells to escape cytotoxic agents. The epineurium and ganglia lack a blood-tissue barrier, and malignant cells could have been eradicated at those sites.