Central Nervous System Involvement of Multiple Myeloma Presenting as Short-lasting Unilateral Neuralgiform Headache with Conjunctival Injection and Tearing: A Case Report.

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA) are part of the trigeminal autonomic cephalalgia (TAC) group of headache disorders. Attacks present with repeated, severe, sharp, stabbing, or throbbing pain. Patients may experience a single attack, recurrent attacks with pain-free interictal periods, or a sawtooth pattern background pain with superimposed stabs. Although SUNCT typically presents as a primary headache disorder, it may be secondary to an underlying pathology, such as pituitary tumors or posterior fossa lesions, both intra and extra-axial (vascular lesion, tumor, or bony abnormalities). Multiple Myeloma (MM) with central nervous system involvement (CNS MM) most commonly presents with visual changes (36%), radiculopathy (27%), headache (25%), confusion (21%), dizziness (7%) and seizures (6%). Secondary SUNCT cases have been sparsely described (less than 60), and CNS MM presenting as SUNCT has not been previously described in the literature. Our case describes a previously unreported clinical presentation of CNS MM. The report highlights the need for a timely and thorough diagnostic work-up of headache in patients with risk factors for a secondary etiology, which in this case included new-onset, autonomic features, older age, and history of malignancy. A misdiagnosis will preclude a potentially life-extending or saving targeted therapy for the underlying illness. We also aim to remind practitioners of the variability in the clinical symptoms of SUNCT, which are known to occur in a significant number of cases, including migrainous features and dull interictal pain.