{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,10]],"date-time":"2026-07-10T11:18:44Z","timestamp":1783682324563,"version":"3.55.0"},"reference-count":13,"publisher":"BMJ","issue":"7","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2026,6,26]]},"published-print":{"date-parts":[[2026,7]]},"abstract":"<jats:p>Monoclonal gammopathy of undetermined significance (MGUS) is traditionally considered a benign precursor plasma cell disorder with minimal risk of progression to multiple myeloma or lymphoproliferative malignancies. However, emerging evidence suggests that MGUS may, in select cases, be associated with clinically significant organ dysfunction. Central nervous system (CNS) involvement remains exceedingly rare.<\/jats:p>\n                  <jats:p>We report a woman in her 70s who presented with subacute visual disturbances. Over 2 years, she developed relapsing, posterior-predominant CNS inflammatory lesions affecting the occipital, temporal and parietal lobes, later extending to involve the pontine and cerebellar regions. Isoelectric focusing and immunofixation of cerebrospinal fluid and serum revealed identical paraprotein bands, implicating a possible pathogenic link between MGUS and CNS pathology.<\/jats:p>\n                  <jats:p>Extensive evaluations did not reveal any alternative explanation for her symptoms, including conditions such as multiple sclerosis, CNS lymphoma, vasculitis or paraneoplastic syndromes. Despite multiple courses of intravenous and oral corticosteroids, she experienced relapses with only moderate clinical improvement.<\/jats:p>","DOI":"10.1136\/bcr-2025-270217","type":"journal-article","created":{"date-parts":[[2026,7,10]],"date-time":"2026-07-10T11:10:14Z","timestamp":1783681814000},"page":"e270217","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Relapsing CNS involvement in MGUS\u2014an Occam\u2019s razor?"],"prefix":"10.1136","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3443-5550","authenticated-orcid":false,"given":"Naveed","family":"Iqbal","sequence":"first","affiliation":[{"name":"Stroke Medicine, Maidstone Hospital, Maidstone, England, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8076-4681","authenticated-orcid":false,"given":"Navraj","family":"Chattha","sequence":"additional","affiliation":[{"name":"Stroke Medicine, Maidstone Hospital, Maidstone, England, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-6624-9589","authenticated-orcid":false,"given":"Alisha","family":"Musthafa","sequence":"additional","affiliation":[{"name":"Stroke Medicine, Maidstone Hospital, Maidstone, England, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ahmed","family":"Hamza","sequence":"additional","affiliation":[{"name":"Stroke Medicine, Maidstone Hospital, Maidstone, England, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,7,10]]},"reference":[{"key":"2026071004100664000_19.7.e270217.1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2141.2006.06235.x"},{"key":"2026071004100664000_19.7.e270217.2","doi-asserted-by":"publisher","DOI":"10.1182\/blood-2017-09-807560"},{"key":"2026071004100664000_19.7.e270217.3","doi-asserted-by":"publisher","DOI":"10.3949\/ccjm.86a.17133"},{"key":"2026071004100664000_19.7.e270217.4","doi-asserted-by":"crossref","first-page":"380","DOI":"10.1182\/hematology.2020000122","article-title":"Monoclonal gammopathies of clinical significance","volume":"2020","author":"Dispenzieri","year":"2020","journal-title":"Hematology"},{"key":"2026071004100664000_19.7.e270217.5","doi-asserted-by":"crossref","first-page":"499","DOI":"10.1182\/hematology.2024000665","article-title":"Neurological manifestations of MGUS","volume":"2024","author":"Cibeira","year":"2024","journal-title":"Hematology Am Soc Hematol Educ Program"},{"key":"2026071004100664000_19.7.e270217.6","doi-asserted-by":"crossref","DOI":"10.1136\/bcr-2020-237726","article-title":"Monoclonal gammopathy of undetermined significance (MGUS) manifestation in CNS: a regular or chance occurrence?","volume":"14","author":"Prakhova","year":"2021","journal-title":"BMJ Case Rep"},{"key":"2026071004100664000_19.7.e270217.7","first-page":"253","article-title":"Unusual association of multiple sclerosis with monoclonal gammopathy of undetermined significance (MGUS): two case reports","volume":"19","author":"Rentzos","year":"2004","journal-title":"Funct Neurol"},{"key":"2026071004100664000_19.7.e270217.8","first-page":"2022","article-title":"Recurrent Optic Neuritis as the First Presentation of Monoclonal Gammopathy of Undetermined Significance (MGUS): A Case Report","volume":"7","author":"Pourmohammadi","year":"2022","journal-title":"Ann Clin 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significance","volume":"03","author":"Gali\u00e8","year":"2013","journal-title":"WJNS"},{"key":"2026071004100664000_19.7.e270217.12","doi-asserted-by":"crossref","first-page":"838","DOI":"10.1016\/j.mayocp.2017.02.003","article-title":"Monoclonal Gammopathy\u2013Associated Peripheral Neuropathy: Diagnosis and Management","volume":"92","author":"Chaudhry","year":"2017","journal-title":"Mayo Clin Proc"},{"key":"2026071004100664000_19.7.e270217.13","doi-asserted-by":"publisher","DOI":"10.1182\/blood-2018-04-839480"}],"container-title":["BMJ Case 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