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.