MSK for Monday, April 7th, 2025

Contributed by Ewha Womans University Medical Center
Hyun-Hae Cho, and Young Hun Choi.

History

10-year-old girl presenting with left leg weakness and burning sensation.

Off therapy for ALL.

What is the most likely diagnosis?

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Neuroleukemiosis

Neuroleukemiosis

Leukemic infiltration of the peripheral nervous system.
Exceedingly rare (<<cranial nerve involvement).
As a relapse of leukemia >> As an initial presentation
With/without CNS involvement, bone marrow and peripheral blood smear abnormality
Apparent BM remission dose not rule out possibility of CNS or PNS involvement by a relapsed leukemic process
Blood-nerve barrier (BNB)
- The tight intercellular junctions make it difficult for leukemic cells to penetrate
- Leukemic cells that have already infiltrated the PNS would potentially be protected from systemic chemotherapeutic drugs.
Radiologic findings
- MR: Thickening of nerve sheath of affected nerve root, T1 isointensity, T2 hyperintensity, homogeneous or heterogenous enhancement
- PET: strong FDG uptake

Vasculitis
Infection (eg herpes)
Paraneoplastic disease
Drug-related neurotoxicity
Immune mediated neuropathy such as chronic inflammatory demyelinating polyneuropathy (CIDP)

Reddy CG, Mauermann ML, Solomon BM, et al. Neuroleukemiosis: an unusual cause of peripheral neuropathy. Leuk Lymphoma. 2012 Dec;53(12):2405-11. Yiu CR, Lee LH, Kumar PM, et al. A patient with extramedullary acute myeloid leukaemia involving the brachial plexus: Case report and review of the literature. Turk J Haematol. 2008 Jun 5;25(2):98-100.