Comment on “Paraneoplastic encephalomyelitis revealing burned-out seminoma”: confirmed case of anti-Kelch-like protein-11 encephalomyelitis

Abstract

Paraneoplastic neurological syndromes occur in association with cancer and have an immune-mediated pathogenesis, but sometimes neuronal antibodies cannot be identified. Recently, Guilmot et al. [1] published a Letter to the Editor describing a case of paraneoplastic encephalomyelitis that led to the diagnosis of a burned-out seminoma, but the patient remained seronegative for all the onconeuronal antibodies known at that time. The 52-year-old patient presented with hearing loss, vertigo, diplopia, nystagmus, and ataxia, and later developed gait difficulties, limb incoordination, and left arm weakness. Repeated brain magnetic resonance imaging (MRI) revealed T2/FLAIR hyperintensities in both thalami, brainstem, and right temporal lobe, while spinal cord imaging showed an extensive myelitis. Cerebrospinal fluid (CSF) studies showed lymphocytic pleocytosis, elevated protein levels, and CSF-specific IgG oligoclonal bands. Given the suspicion of a paraneoplastic syndrome, an extensive workup was performed and revealed a para-aortic nodal metastasis of a burned-out seminoma. Despite orchiectomy, radiotherapy, and multiples lines of immunotherapy, the patient died 16 months after symptom onset.Kelch-Like Family Member 11 (KLHL11) is an intra-cellular protein involved in ubiquitination [2]. Autoantibodies * Vincent van Pesch

Paraneoplastic Kelch-like protein 11 antibody-associated cerebellar and limbic encephalitis caused by metastatic “burned-out” seminoma – A scar(r)y phenomenon

“…Our report highlights the importance of detailed and repeated investigations for testicular cancer in male patients between the ages of 20-50 with suspected PNS, since it is the second most common malignancy in this patient cohort, and the first most common between 20 and 40 years of age (Ward et al, 2019). The number of reports describing PNS associated with burned-out testicular tumor is limited (Vogrig et al, 2021;Chen et al, 2021;Guilmot et al, 2021;Maldonado Slootjes et al, 2022;Onishi et al, 2014;Freifeld et al, 2018;Ishikawa et al, 2016;van de Warrenburg et al, 2007), and it is tempting to speculate that at least some of them might have been associated with KLHL11 autoantibodies (Maldonado Slootjes et al, 2022).…”

Anti‐kelchlike protein 11 antibody‐associated encephalitis: Two case reports and review of the literature

“…So far, 112 patients with KLHL11‐IgG‐associated encephalitis have been reported in the literature (Table 1) [9, 11–20, 23–28].…”

“…developed progressive vertigo, and truncal and appendicular ataxia almost 4 years after diagnosis of and therapy for a testicular seminoma [9]. So far, 112 patients with KLHL11-IgG-associated encephalitis have been reported in the literature (Table 1) [9,[11][12][13][14][15][16][17][18][19][20][23][24][25][26][27][28].…”