429 - A Rare Presentation of Neuromyelitis Optica Paraneoplastic Myelopathy secondary to Lung Squamous Cell Carcinoma: a Case Report

Case Diagnosis: Anti-AQP4 antibody positive paraneoplastic Neuromyelitis Optica secondary to squamous cell carcinoma of the lung.

Case Description: A 65 year old man with history of prior colon cancer presented with one day of left greater than right lower extremity weakness and urinary retention measuring greater than 1 liter. His exam was notable for decreased sensation below the T2 dermatome, decreased strength in bilateral hip flexors and left plantarflexion/dorsiflexion, and absent voluntary anal contraction; no vision abnormalities were noted. MRI revealed abnormal cord signal from C4 to T12, and CT chest/abdomen/pelvis noted an 8cm lung mass. Corticosteroids were initiated, and biopsy of the mass confirmed squamous cell carcinoma. Oncology was consulted for concern for paraneoplastic syndrome and chemotherapy was started inpatient. Lumbar puncture was negative. Laboratory testing later revealed positive Neuromyelitis Optica anti-AQP4 (NMO-IgG) antibodies. The patient’s treatment with plasma exchange therapy and further inpatient laboratory workup is ongoing.

Discussions: Neuromyelitis Optica Spectrum Disorder (NMOSD), or Devic’s Disease, is a autoimmune disease resulting from autoantibodies against the water channel aquaporin-4 (AQP4-IgG). Distinct from Multiple Sclerosis, this disease is a relapsing inflammatory demyelinating process presenting with optic neuritis and transverse myelitis. Paraneoplastic NMOSD is an rare presentation resulting from remote immune-mediated mechanisms in association with cancer. The most commonly associated neoplasms described in the literature include genitourinary, breast, and lung cancers, with a minority (21%) of patients being male. In a recent systematic review, lung squamous cell carcinoma represented only 3% of overall cases described. Complete recovery with appropriate treatment of those experiencing their first attack of NMOSD was seen in 34.9% of patients with the majority showing partial recovery.

Conclusions: Our patient represents a rarity in NMOSD and an example of a clinical presentation not to miss. Recovery is possible if treatment is started during the initial attack, thus prompt identification of such patients is critical.