Diplopia and Variable Ptosis as the Sole Initial Findings in a Case of Orbital Plasmacytoma and Multiple Myeloma

Plasmacytomas are monoclonal plasma cell tumors. They represent 3% of all orbital tumors. We present an unusual case of orbital plasmacytoma and advanced multiple myeloma where the sole presenting symptoms were those of diplopia and ptosis. Clinical examination revealed right hypertropia and variable left upper lid ptosis but no proptosis. The visual acuity and the rest of the ocular examination were normal in both eyes. An MRI scan of the brain and orbits revealed a frontal bone lesion consistent with a plasmacytoma. A bone marrow biopsy showed a light chain multiple myeloma with free lambda light chains. Although the literature reports diplopia and ptosis as being clinical features of orbital plasmacytomas, to our knowledge this is the first reported case where these symptoms were the only presenting features, despite widespread disease.