Unusual presentation of multiple myeloma with unilateral visual loss and numb chin syndrome in a young adult.

A 39-year-old man presented with unilateral visual loss as the first sign of multiple myeloma (MM). His visual loss was due to a plasmacytoma in the sphenoid sinus compressing the optic nerve with resultant optic nerve atrophy. Shortly after this presentation he developed numb chin syndrome due to a mandibular plasmocytoma compressing the mental nerve. His MM progressed rapidly despite treatment with high-dose steroids and alkylating agents and he required allogeneic bone marrow transplantation in order to achieve a remission. We reviewed the published medical literature on the presentation of MM with visual impairment and present a summary in tabular form in this paper. This is the first reported case of MM presenting with isolated complete visual loss due to intracranial extrinsic compression of the optic nerve since the advent of modern cross-sectional imaging. Multiple myeloma needs to be included in the differential diagnosis of cranial neuropathies and skull base neoplasms even in adults under 40 years of age.