Anti-Yo antibody-positive paraneoplastic cerebellar degeneration in a patient with possible cholangiocarcinoma:A case report and review of the literature

Paraneoplastic cerebellar degeneration(PCD),which is rare in clinical practice,is closely related to autoimmunity.Cases positive for anti-Yo antibodies(anti-Purkinje cytoplasmic antibody 1)are the main subtype of PCD.PCD is subacute cerebellar degeneration,and while it progresses over weeks to months,its resultant deficits last much longer.Cancer patients with anti-Yo antibody-positive PCD are very rare.Most of them are breast cancer or ovarian cancer patients but also occasionally lung cancer patients.CASE SUMMARY A 61-year-old woman presented with sudden vertigo,nausea,and vomiting for approximately 10 d.The patient's neurological examination showed torsion with downbeat nystagmus and ataxia of the right limb and trunk.Laboratory examination found that the patient's cerebrospinal fluid and serum were anti-Yo antibody-positive,positron emission tomography computed tomography showed an increased metabolic rate in the retroperitoneal lymph nodes,and the pathology of lymph node punctures in the retroperitoneum and neck suggested adenocarcinoma of the pancreaticobiliary duct,which strengthens the hypothesis of paraneoplastic origin.Intravenous immunoglobulin(IVIg)0.4 g/kg/d for 5 d and methylprednisolone 160 mg for 3 d were initiated,which was reduced to 80 mg for 3 d and then to 40 mg for 7 d.After treatment with IVIg and a steroid,the patient's vertigo and ataxia alleviated.CONCLUSION The patient's vertigo and ataxia alleviated after treatment,suggesting that early immunotherapeutic intervention may have certain value in stopping neurological loss.

A Rare Case of Ovarian Cancer Presenting with Paraneoplastic Cerebellar Degeneration and Limbic Encephalitis

Paraneoplastic neurologic syndromes （PNSs） occur with increased frequency in patients with cancer and almost always antedate its diagnosis.These syndromes comprise a heterogeneous group of cancer-related neurologic diseases,and they may affect any part of the nervous system.The simultaneous involvement of different areas of the nervous system by the paraneoplastic process is not unusual.Until date,this is the first report of concurrent development of paraneoplastic cerebellar degeneration （PCD） and paraneoplastic limbic encephalitis （PLE） associated with the advanced ovarian cancer and anti-Yo antibodies following hepatitis B （HB） vaccination.The cause of most PNS is believed to be an immune response against neuronal proteins expressed by the tumor.

Paraneoplastic cerebellar degeneration associated with somatic mutations in ultra-early diagnosis of small cell lung cancer: a case report

Paraneoplastic cerebellar degeneration(PCD)can occur in patients with underlying cancer,such as small cell lung cancer(SCLC).Anti-CV2/CRMP5 antibodies are well-established biomarkers of PCD associated with SCLC,but cannot be detected in most situations.Recently,next-generation sequencing has been a promising technology to discover cancer-driven mutations,which provide an alternative strategy to accomplish ultra-early diagnosis of those patients.Here,we report the case of a 75-year-old man diagnosed with SCLC,who primarily presented with anti-CV2/CRMP5 antibodies positive PCD.Eight high-frequency gene mutations(TSC2,DNMT1,CIC,FGF6,NSD1,TSHR,CRLF2,and EPPK1)were detected 7 months before diagnosis with no abnormalities of imaging or cerebrospinal fluid examination found initially.Therefore,this case suggests the possibility of detecting certain somatic mutations for the ultra-early diagnosis of patients presenting with PCD associated with SCLC.

Voltage gated calcium channel antibody-related neurological diseases

Voltage gated calcium channel(VGCC) antibodies are generally associated with Lambert-Eaton myasthenic syndrome. However the presence of this antibody has been associated with paraneoplastic as well as nonparaneoplastic cerebellar degeneration. Most patients with VGCC-antibody-positivity have small cell lung cancer(SCLC). Lambert-Eaton myasthenic syndrome(LEMS)is an autoimmune disease of the presynaptic part of the neuromuscular junction. Its classical clinical triadis proximal muscle weakness, areflexia and autonomic dysfunction. Fifty to sixty percent of LEMS patients have a neoplasia, usually SCLC. The co-occurrence of SCLC and LEMS causes more severe and progressive disease and shorter survival than non-paraneoplastic LEMS. Treatment includes 3,4 diaminopyridine for symptomatic purposes and immunotherapy with prednisolone, azathioprine or intravenous immunoglobulin in patients unresponsive to 3,4 diaminopyridine. Paraneoplastic cerebellar degeneration(PCD) is a syndrome characterized with severe, subacute pancerebellar dysfunction. Serum is positive for VGCC antibody in 41%-44% of patients, usually with the co-occurrence of SCLC. Clinical and electrophysiological features of LEMS are also present in 20%-40% of these patients. Unfortunately, PCD symptoms do not improve with immunotherapy. The role of VGCC antibody in the immunopathogenesis of LEMS is well known whereas its role in PCD is still unclear. All patients presenting with LEMS or PCD must be investigated for SCLC.