Case Presentation: A 55 year-old man presented with a subacute history of difficulty swallowing.  The patient was being treated with ezotuzumab and lenalidomide for Stage II IgG kappa light chain multiple myeloma. He had recently received zoludronic acid for treatment of asymptomatic hypercalcemia.  Neurological exam was remarkable only for reduced upper extremity strength (4/5 Medical Research Council) bilaterally. Cranial nerve exam was normal. White blood count was 4.6 K/uL with a normal peripheral smear. Serum ionized calcium was normal at 1.19 mmoles/L. IgG was elevated at 2590 mg/dL with depression of IgA and IgM levels. Kappa free light chains were elevated at 3.55 mg/dL.  Serum viscosity was normal at 1.2 cP.  Anti-acetylcholine receptor antibody assay was normal. CAT of the head and neck was remarkable only for diffuse bone marrow heterogeneity.  MRI of the brain and brainstem was normal.  Cine-esophogram demonstrated a severe impairment of swallowing, with tongue dysfunction, poor epiglottic inversion, and significant pooling of contrast material in the vallecula and proximal esophagus. Endoscopic examinations of the nasopharynx and esophagus were without any evidence of structural abnormality.  Lumbar puncture demonstrated 8 wbc/uL, which on cytospin exam were identified as atypical plasma cells with eccentric nuclei, prominent nucleoli, and noted mitotic figures (Figure 1).  Treatment for leptomeningeal myeloma was initiated with intrathecal methotrexate and cranial radiation.

Discussion: Central nervous system involvement occurs in only 1% of multiple myeloma patients, and may be due to localized parenchymal infiltration, cerebral plasmacytoma, or leptomeningeal involvement. CNS myelomatosis is defined as the presence of monoclonal plasma cells in the CSF. CNS myeloma may present with headache, altered mental status, gait abnormality, or cranial nerve palsies. Isolated dysphagia as the initial presentation of CNS multiple myeloma has not been previously described.  In this patient, without evidence of macroscopic tumor presence, isolated cranial nerve impairment through direct microscopic infiltration is the postulated pathophysiology. The prognosis of patients with CNS multiple myeloma is poor. Untreated patients survive a median of 3 weeks, versus 3 months in those treated with cranial irradiation and intrathecal chemotherapy.

Conclusions: Isolated dysphagia has not been previously described as a presentation of CNS multiple myeloma.  This unique case reinforces the concept that a heightened degree of clinical suspicion, and an aggressive diagnostic evaluation are necessary for the early diagnosis and prompt treatment of CNS multiple myeloma, where time is of the essence for improved survival.