Exploring Age-Dependent Differences in KLHL11 IgG Associated Paraneoplastic Rhombencephalitis (S18.007)

Objective: Evaluate age-related differences in clinical characteristics and outcomes among patients with Kelch-like protein-11 Immunoglobulin G seropositive (KLHL11 IgG+) associated paraneoplastic neurologic syndrome (PNS). Background: KLHL11 IgG+ PNS is a disabling syndrome often associated with younger patients with testicular germ cell tumor (TGCT). Recently other tumors and older patients have been reported. Design/Methods: Retrospective review of Mayo Clinic Database and Neuroimmunology Laboratory database. Results: Sixty patients (median age 45 years (IQR 24–73; 97% male) with a KLHL11 IgG+ PNS were identified, of which 23 were classed as older (>50). Among older patients, 16/20 (median age 62, range 51–73, 9% females) had an underlying cancer (seminomatous TGCT n=11; 69%, non-testicular cancer (NTC) n=5, 31%). Presentation of TGCT was extragonadal in 4/11 (36%). NTCs included esophageal cancer, lung adenocarcinoma, B-cell lymphoma, chronic lymphocytic leukemia and Mullerian Cancer. Presenting features included ataxia (78%), diplopia (57%), vertigo (57%) and dysarthria/dysphagia (48%). MRI was abnormal in 14/21 (61%), with cerebellar atrophy (n=4) most common, and CSF had inflammatory changes in 15/19 (65%). Of the 19 patients treated with immunotherapy, six had improvement, eight had stabilization, and five had progression of their symptoms, with a median surveillance time of 24 months. Thirteen patients had an MRS >= 3 at last follow-up. Compared to the younger cohort NTC was more frequent in patients >50 years (p=0.004). There was no significant difference in clinical features, imaging abnormalities and outcomes in the total cohort or the paraneoplastic cohort Conclusions: KLHL11 IgG+ PNS is infrequently linked to non-testicular cancer, and more often observed in individuals >50. Patients within this demographic presenting with signs indicative of rhombencephalitis should be carefully evaluated, as there is potential for improvement, although overall prognosis for this syndrome remains unfavorable. Disclaimer: Abstracts were not reviewed by Neurology® and do not reflect the views of Neurology® editors or staff. Disclosure: Dr. Harinesan has nothing to disclose. Dr. Harahsheh has nothing to disclose. Dr. Aboseif has a non-compensated relationship as a AAN Autoimmune Neurology Section -- Education Workgroup with AAN that is relevant to AAN interests or activities. Dr. Mokhtari has nothing to disclose. Dr. Gupta has nothing to disclose. Dr. Pittock has received personal compensation in the range of $500-$4,999 for serving as a Consultant for UCB. Dr. Pittock has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Arialys Therapeutics. The institution of Dr. Pittock has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion. Dr. Pittock has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Arialys. The institution of Dr. Pittock has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for UCB. The institution of Dr. Pittock has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Roche/Genentech. The institution of Dr. Pittock has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Alexion/AstraZeneka. The institution of Dr. Pittock has received research support from NIH. The institution of Dr. Pittock has received research support from Alexion/AstraZeneka. The institution of Dr. Pittock has received research support from F. Hoffman/LaRoche/Genentech. Dr. Pittock has received intellectual property interests from a discovery or technology relating to health care. Dr. Pittock has received intellectual property interests from a discovery or technology relating to health care. Dr. Pittock has received publishing royalties from a publication relating to health care. The institution of Dr. Dubey has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Argenx. The institution of Dr. Dubey has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Arialys. The institution of Dr. Dubey has received personal compensation in the range of $500-$4,999 for serving as a Consultant for UCB . Dr. Dubey has received research support from Department of Defense . Dr. Dubey has received research support from Department of Defense . Dr. Dubey has received research support from UCB. Dr. Dubey has received research support from David J. Tomassoni ALS Research Grant Program . Dr. Dubey has received intellectual property interests from a discovery or technology relating to health care. Dr. Dubey has received intellectual property interests from a discovery or technology relating to health care. Dr. Dubey has received intellectual property interests from a discovery or technology relating to health care. Dr. Dubey has received intellectual property interests from a discovery or technology relating to health care.