A 49-year-old female presented to the emergency department for 2 months of ascending leg weakness and numbness. Exam was notable for bilateral lower extremity weakness (distal worse than proximal), decreased vibratory sensation below the knees, and absent patellar reflexes. MRI Lumbar Spine showed cauda equina nerve root enhancement. CSF studies demonstrated elevated protein (67) and glucose (138) and no nucleated cells.  Presumed diagnosis was chronic inflammatory demyelinating polyneuropathy (CIDP), and she was treated with IVIG for 4 days with minimal improvement and discharged to inpatient rehab.

Bloodwork was notable for mild thrombocytosis and monoclonal gammopathy with lambda predominance. Body CTs showed prominent left supraclavicular nodes, hepatomegaly, and pelvic sclerotic lesions. Subsequent autoimmune workup from this admission was positive for neurofascin(NF)-140.  

Two months later, she returned to the hospital for worsening leg weakness and new bilateral hand weakness. Suspecting a CIDP flare, she was treated with high-dose steroids, PLEX, and IVIG but did not improve. She was discharged with plans to initiate outpatient Rituximab for nodopothy-type CIDP.

On outpatient re-review of her case, POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes) was suspected. Vascular endothelial growth factor (VEGF) level was ordered and markedly elevated (885). She was referred to Malignant Hematology who confirmed the diagnosis and initiated chemotherapy.

Subacute ascending leg weakness with suggestive MRI and CSF findings often leads to the diagnosis of CIDP. NF-140 seropositivity would be confirmatory and explain a poor response to standard therapy (steroids and IVIG). However, the constellation of the above findings should have also raised concern for POEMS. An elevated VEGF level is typical of POEMS and unexpected in CIDP, and this test likely would have changed management if performed earlier. Although neurofascin autoantibody is usually considered specific for nodopathy-type CIDP, it may also be found in rare cases of POEMS.