Diagnostic challenges in POEMS syndrome presenting with polyneuropathy: A case series.

OBJECTIVE: To analyze the clinical characteristics of patients with POEMS presenting with polyneuropathy and discuss associated diagnostic challenges.

METHOD: Retrospective analysis of 6 patients from 2 tertiary-care institutions.

RESULTS: Six patients presented with progressive sensorimotor deficits predominantly or exclusively in the lower extremities and were diagnosed with POEMS syndrome. In 4 patients, a diagnosis of chronic inflammatory demyelinating polyradiculopathy (CIDP) was mistakenly made. Low concentration of serum paraprotein and elevated vascular endothelial growth factor (VEGF) were detected in all 6 patients. Initial serum immunofixation and skeletal survey were normal in 2 patients each. On nerve conduction studies, motor and sensory responses were absent in the lower extremity in all 6 patients. Conduction velocity slowing and F-wave latency prolongation appear slightly more pronounced than distal motor latency prolongation in the upper extremity. Spinal MRI showed diffuse lumbosacral nerve root enhancement in all. In 3 patients, targeted bone marrow biopsy was needed for confirming the POEMS diagnosis. Treatment with corticosteroids, chemotherapy agent, focal radiation and/or autologous stem cell transplantation led to significant improvement in 5 of 6 patients.

CONCLUSION: Diagnosis of POEMS should be considered in patients with progressive polyneuropathies of mixed demyelinating and axon loss features, including CIDP patients not responding to standard treatment. A polyradiculoneuropathy rather than a pure polyneuropathy seems to exist in POEMS.