SESSION TITLE: Lung Cancer 1 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Paraneoplastic neurologic syndromes (PNS) are rare but clinically important complications of malignancy. These syndromes occur in approximately 0.01% of cancer patients, although more frequently in those with lung cancer, specifically small cell carcinoma. The neurologic syndromes are extensive and may present as encephalomyelitis, cerebellar cortical degeneration, peripheral neuropathy, neuopsoclonus-myoclonus, and retinopathy[1]. CASE PRESENTATION: A 76-year old woman with a recent diagnosis of well differentiated adenocarcinoma, mixed acinar and micropapillary, KRAS p.Gly12Val tumor marker positive, type lung cancer, presented with shortness of breath and altered mental status. According to family she was becoming progressively confused for the prior six weeks, displaying “hyper-somnolence” and speaking “with her eyes closed”. Neurological exam was significant for lethargy, confusion, and incoherent speech. Admission labs showed elevated WBC count 15.7; lactate 0.8. Chest X-ray showed patchy opacities bilaterally, and mild pulmonary congestion. CT scan of her brain was negative for acute pathology. Brain MRI was negative for metastatic disease. Empiric treatment for pneumonia was initiated based on x-ray findings. During her hospital stay, patient remained minimally communicative and unable to follow commands. VEEG was unremarkable. CSF analysis showed 5 WBC, no RBC, with 48% lymphocytes, and 48% monocytes. CSF cytology was negative for malignant cells. Elevated protein was measured at 81 mg/dL. CSF PCR was negative for VZV, HSV, and West Nile Virus. Paraneoplastic encephalitis was suspected due to lack of alternative etiologies for the patient’s symptoms. Treatment with IVIG and high-dose solumedrol was initiated. Ultimately, the paraneoplastic antibody panel resulted with type I anti-neuronal nuclear antibody (ANNA-1) titer of 1:512, Anti-Hu AB titer of 1:32, and anti-recoverin titer of 1:1. DISCUSSION: Paraneoplastic neurologic syndromes are rare clinical syndromes, resulting from the remote effect of a tumor on the nervous system, associated 95% of the time with small cell lung cancer [2]. Our patient’s manifestation of PNS with lung adenocarcinoma is extremely rare. Due to the very low incidence of non-small cell lung cancer associated with PNS, her diagnosis of lung adenocarcinoma was not believed to be contributory to her change in mental status. However, discovery of well characterized onconeural proteins such anti-Hu antibodies in the CSF, made a diagnosis of a PNS highly likely. CONCLUSIONS: Our case demonstrates that lung adenocarcinoma can play a role in the development of paraneoplastic neurologic syndrome and should be considered in the setting of a patient with altered mental status without other cause. Reference #1: Miyamoto, K., et al., A case of paraneoplastic syndrome accompanied by two types of cancer. J Neurol Neurosurg Psychiatry, 2002. 72(3): p. 408-9. Reference #2: Kanaji, N., et al., Paraneoplastic syndromes associated with lung cancer. World J Clin Oncol, 2014. 5(3): p. 197-223. DISCLOSURES: No relevant relationships by Scott Ferrara, source=Web Response No relevant relationships by eman rashed, source=Web Response No relevant relationships by Peter Rattner, source=Web Response No relevant relationships by Michael Silverberg, source=Web Response