Waldenström’s disease (WD) is frequently associated with a predominantly sensory neuropathy with a progressive course due to the monoclonal IgM activity against Myelin Associated Glycoprotein (MAG). However, neurolymphomatosis or chronic demyelinating inflammatory polyneuropathy (CDIP) may occur in some patients with WD.Case report We report a case of Waldenström’s macroglobulinemia in an adult male presenting with cranial nerve palsy and rapidly progressive asymmetric polyneuropathy. Intravenous IgM treatment that provided transient amelioration was followed by a relapse involving tetraparesis. Cerebrospinal fluid analysis, medullar magnetic resonance imaging, and electrophysiological studies led to equivocal findings suggesting the presence of either neurolymphomatosis or CIDP. Finally, sural nerve biopsy results supported the diagnosis of CIDP, which then received appropriate treatment. Conclusion In patients with WD, the possible occurrence of CIDP should be investigated with a neuromuscular biopsy when other investigations are equivocal since the disease calls for a specific treatment.