Hypoglossal Nerve Mononeuropathy as the First Presenting Symptom of Progressing Multiple Myeloma.

Multiple myeloma (MM) rarely presents with a primary neurological dysfunction, and if it does it is usually due to a plasmacytoma. This is the first case to discuss hypoglossal nerve dysfunction as the first sign of MM progression secondary to severe pathophysiologic bone lysis. A PubMed-based literature search was completed on April 17, 2016 for the terms "multiple myeloma" and "hypoglossal nerve neuropathy". A 73-year-old woman with known MM who received little treatment for several years, presented secondary to dysarthria and at first was thought to have hyperviscosity syndrome. On further examination, it was found she had light chain disease and her symptoms were secondary to severe disease progression. Imaging revealed multiple lytic lesions in the skull on skeletal survey and brain MRI revealed boney lysis near the occipital condyle and clivus likely interfering with the coursing of the hypoglossal nerve. Advanced progressing MM can cause severe boney destruction which can interfere with cranial nerve canals and cause neuropathy as a presenting symptom.