A rare neurological adverse event of palbociclib: a chronic inflammatory demyelinating polyneuropathy (CIDP) mimic.
Joy Zeynoun, Madeline Evans, Kimberly Boldig et al.
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Case in brief
A 43-year-old woman with metastatic HR-positive/HER2-negative breast cancer developed progressive, asymmetric weakness and sensory symptoms about two weeks after starting palbociclib. Electrodiagnostic testing showed a mixed axonal and demyelinating sensorimotor polyneuropathy meeting criteria for acquired inflammatory demyelinating polyradiculoneuropathy. Initial considerations included AIDP and multifocal CIDP. Symptoms progressed despite initial improvement with IVIG, prompting plasmapheresis, repeat IVIG, high-dose corticosteroids, and rituximab. Testing identified anti-neurofascin-155 and anti-neurofascin-186 antibodies; follow-up showed significant functional recovery after rituximab.
What made this case unusual
The neuropathy had a CIDP-like presentation with anti-neurofascin antibodies and arose soon after palbociclib initiation; the report suggests a possible association, not a proven causal relationship.
Diagnostic / clinical pearl
Progressive weakness and sensory deficits during CDK4/6 inhibitor therapy warrant consideration of an immune-mediated neuropathy; electrodiagnostic findings and antibody testing may help characterize the syndrome.