Multiple myeloma with plasmacytoma of the clivus bone presenting with multiple cranial nerve III, IV, and VI palsy: A diagnostic dilemma.

Central nervous system (CNS) manifestation with cranial nerve palsy in multiple myeloma (MM) is a rare manifestation. Plasmacytoma originates from the bones of the skull base in 3% patients with MM but rarely develops from the soft tissues of the nasal cavity and paranasal sinuses. Here, we present a case of 68-year-old male patient with multiple myeloma, clivus bone plasmacytoma, and cavernous sinus syndrome.