{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T12:12:26Z","timestamp":1783944746345,"version":"3.55.0"},"reference-count":20,"publisher":"BMJ","issue":"7","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2026,5,31]]},"published-print":{"date-parts":[[2026,7]]},"abstract":"<jats:p>Paraneoplastic neurological syndromes (PNS) associated with triple-negative breast carcinoma (TNBC) are exceptionally rare. We report a case of fulminant encephalitis in a middle-aged woman with TNBC presenting with concurrent PNMA2 (Ma2\/Ta), ZIC4 and recoverin antibody positivity. The patient initially developed a subacute cerebellar syndrome characterised by downbeat nystagmus, gait ataxia and diplopia. Comprehensive evaluation revealed FDG-avid left axillary lymphadenopathy and biopsy confirmed high-grade TNBC with PD-L1 CPS of 77. She received neoadjuvant chemo-immunotherapy as per standard institutional protocol (paclitaxel, carboplatin, epirubicin, cyclophosphamide and pembrolizumab). Following the sixth cycle, she developed refractory focal seizures progressing to status epilepticus with MRI findings consistent with cortical encephalitis. Despite aggressive immunosuppression including corticosteroids, intravenous immunoglobulin and rituximab, her condition proved refractory. She ultimately succumbed despite maximal supportive care. This case illustrates a rare paraneoplastic overlap syndrome combining PNMA2-associated encephalitis and ZIC4-associated cerebellar degeneration in TNBC, highlights diagnostic challenges when immune checkpoint inhibitors may amplify pre-existing onconeural immunity and underscores the dismal prognosis of intracellular antibody-mediated neurological syndromes despite aggressive immunotherapy.<\/jats:p>","DOI":"10.1136\/bcr-2025-269510","type":"journal-article","created":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T11:35:15Z","timestamp":1783942515000},"page":"e269510","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Fulminant paraneoplastic Ma2 (PNMA2) and zinc finger protein of the cerebellum 4 (ZIC4) antibody-positive encephalitis in triple-negative breast cancer treated with pembrolizumab"],"prefix":"10.1136","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-3802-3432","authenticated-orcid":false,"given":"Prabhat","family":"Gautam Roy","sequence":"first","affiliation":[{"name":"Medical Oncology, All India Institute of Medical Sciences New Delhi, New Delhi, New Delhi, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aniket B","family":"Jagtap","sequence":"additional","affiliation":[{"name":"Medical Oncology, All India Institute of Medical Sciences New Delhi, New Delhi, New Delhi, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ajay","family":"Gogia","sequence":"additional","affiliation":[{"name":"Medical Oncology, All India Institute of Medical Sciences New Delhi, New Delhi, New Delhi, India"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,7,13]]},"reference":[{"key":"2026071304350796000_19.7.e269510.1","doi-asserted-by":"publisher","DOI":"10.1136\/jnnp.2003.034447"},{"key":"2026071304350796000_19.7.e269510.2","doi-asserted-by":"publisher","DOI":"10.1016\/S1474-4422(15)00401-9"},{"key":"2026071304350796000_19.7.e269510.3","doi-asserted-by":"publisher","DOI":"10.1093\/brain\/awh203"},{"key":"2026071304350796000_19.7.e269510.4","doi-asserted-by":"publisher","DOI":"10.1111\/j.1468-1331.2006.01266.x"},{"key":"2026071304350796000_19.7.e269510.5","doi-asserted-by":"publisher","DOI":"10.1002\/ana.20269"},{"key":"2026071304350796000_19.7.e269510.6","doi-asserted-by":"crossref","first-page":"1481","DOI":"10.1093\/brain\/123.7.1481","article-title":"Paraneoplastic limbic encephalitis: neurological symptoms, immunological findings and tumour association in 50 patients","volume":"123 (Pt 7)","author":"Gultekin","year":"2000","journal-title":"Brain"},{"key":"2026071304350796000_19.7.e269510.7","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.nrleng.2016.05.004","article-title":"Anti-Ma and anti-Ma2-associated paraneoplastic neurological syndromes","volume":"33","author":"Ortega Suero","year":"2018","journal-title":"Neurolog\u00eda (English Edition)"},{"key":"2026071304350796000_19.7.e269510.8","doi-asserted-by":"publisher","DOI":"10.1056\/NEJM199906103402303"},{"key":"2026071304350796000_19.7.e269510.9","doi-asserted-by":"publisher","DOI":"10.1136\/jnnp.2007.118588"},{"key":"2026071304350796000_19.7.e269510.10","doi-asserted-by":"crossref","first-page":"97","DOI":"10.47936\/encephalitis.2023.00080","article-title":"Atypical occurrence of anti-Ma2-associated encephalitis after breast cancer surgery and COVID-19","volume":"3","author":"Seo","year":"2023","journal-title":"Encephalitis"},{"key":"2026071304350796000_19.7.e269510.11","article-title":"Anti-Zic4 Paraneoplastic Cerebellar Degeneration With Mesial Temporal Lobe Hyperintensity in a Patient With Papillary Thyroid Carcinoma: A Case Report and Review of the Literature","volume":"15","author":"Abuzahra","year":"2023","journal-title":"Cureus"},{"key":"2026071304350796000_19.7.e269510.12","first-page":"163","article-title":"Paraneoplastic cerebellar degeneration associated with breast cancer: A case report and review of the literature","volume":"9","author":"Yan","year":"2018","journal-title":"Mol Clin Oncol"},{"key":"2026071304350796000_19.7.e269510.13","doi-asserted-by":"crossref","DOI":"10.1001\/archneurol.2011.176","article-title":"Isolated ZIC4 antibodies in paraneoplastic cerebellar syndrome with an underlying ovarian tumor","volume":"68","author":"Kerasnoudis","year":"2011","journal-title":"Arch Neurol"},{"key":"2026071304350796000_19.7.e269510.14","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1016\/j.jneuroim.2008.01.018","article-title":"ZIC antibodies in paraneoplastic cerebellar degeneration and small cell lung cancer","volume":"201\u2013202","author":"Sabater","year":"2008","journal-title":"J Neuroimmunol"},{"key":"2026071304350796000_19.7.e269510.15","doi-asserted-by":"publisher","DOI":"10.1136\/jnnp.74.9.1332"},{"key":"2026071304350796000_19.7.e269510.16","doi-asserted-by":"publisher","DOI":"10.1016\/j.jtho.2017.08.007"},{"key":"2026071304350796000_19.7.e269510.17","unstructured":"Vogrig - Triggering factors and immunopathogenesis of paran.pdf, Available: https:\/\/theses.hal.science\/tel-03917161\/file\/TH2021VOGRIGALBERTO.pdf [Accessed 17 Aug 2025]."},{"key":"2026071304350796000_19.7.e269510.18","doi-asserted-by":"crossref","DOI":"10.1186\/s40425-019-0821-8","article-title":"Worsening and newly diagnosed paraneoplastic syndromes following anti-PD-1 or anti-PD-L1 immunotherapies, a descriptive study","volume":"7","author":"Manson","year":"2019","journal-title":"J Immunother Cancer"},{"key":"2026071304350796000_19.7.e269510.19","doi-asserted-by":"publisher","DOI":"10.3988\/jcn.2016.12.1.1"},{"key":"2026071304350796000_19.7.e269510.20","doi-asserted-by":"publisher","DOI":"10.1093\/brain\/awg133"}],"container-title":["BMJ Case Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bcr-2025-269510","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T11:35:16Z","timestamp":1783942516000},"score":1,"resource":{"primary":{"URL":"https:\/\/casereports.bmj.com\/lookup\/doi\/10.1136\/bcr-2025-269510"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7]]},"references-count":20,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2026,7,13]]},"published-print":{"date-parts":[[2026,7]]}},"alternative-id":["10.1136\/bcr-2025-269510"],"URL":"https:\/\/doi.org\/10.1136\/bcr-2025-269510","relation":{},"ISSN":["1757-790X"],"issn-type":[{"value":"1757-790X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7]]}}}