Objective:

To describe a case of lumbosacral radiculopathy as the initial recurrence of extramedullary acute myelogenous leukemia (AML). 

Background:

While AML can infiltrate nerve roots and peripheral nerves (termed neuroleukemiosis), the rarity of extramedullary nerve root involvement as the initial manifestation of AML can lead to delay in diagnosis and treatment. 

Design/Methods:

Case report with review on this topic.

Results:

A 40-year-old male with AML in remission for 6 years presented with 3 weeks of radiating back pain, progressive left leg numbness and foot drop, and right arm forearm numbness. Neurological examination disclosed profound weakness (2/5 MRC) in the left L5-S1 myotomes and 3-4/5 in the left L2-4 myotomes. Sensation was reduced in the lateral left leg and foot and medial right forearm. Reflexes were diminished in the right arm and absent in the left leg but were otherwise normal. Bloodwork did not reveal evidence of peripheral blood dyscrasias and Oncology felt the chance of AML recurrence was low. EMG demonstrated left > right lumbosacral intraspinal canal lesions affecting the L2-S1 nerve roots/segments. MRI of the cervical, thoracic, and lumbar spine showed asymmetric thickening and enhancement of the left L3-S1 nerve roots. Lumbar puncture revealed markedly atypical and enlarged cells and 78.5% abnormal blast population expressing CD 34, CD117, CD45, and CD7, consistent with AML. Recurrent AML was confirmed with bone marrow analysis and treatment with intrathecal methotrexate and high-dose cytarabine initiated. One month after treatment this patient’s spinal fluid showed resolution of abnormal cells and he experienced modest improvement in symptoms. 

Conclusions:

This case highlights that patients with acute multifocal polyneuropathy or radiculopathy and in the presence of red flags, such as cancer or even AML in remission, require appropriate imaging and when indicated, spinal fluid analysis with cytology and flow cytometry.