Painful neuropathy due to intraneural leukemic spread in a patient with acute myeloid leukemia.

A 33-year-old man with acute myelogenous leukemia developed a rapidly progressive painful neuropathy with symmetric sensorimotor and autonomic deficits 7 weeks after chemotherapy. Nerve conduction studies showed axonal sensorimotor neuropathy. Because of the rapidly progressive course, a sural nerve biopsy was performed, which showed intraneural leukemic infiltrates (figure). This case illustrates a rare but important differential diagnosis in patients with peripheral neuropathy and hematologic malignancies.1,2 The diagnosis would have been missed without a sural nerve biopsy, and aggressive chemotherapy might have been withheld owing to presumed toxic neuropathy as a result of previous chemotherapy.