{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T17:30:34Z","timestamp":1787074234832,"version":"build-2736575974"},"reference-count":11,"publisher":"BMJ","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["Pract Neurol"],"accepted":{"date-parts":[[2026,6,28]]},"abstract":"<jats:p>\n                    Primary diffuse leptomeningeal melanomatosis (PDLM) is an exceptionally rare and aggressive central nervous system melanocytic tumour, often masquerading as inflammatory or infective leptomeningeal disease. A woman in her early 60s presented with hydrocephalus and diffuse leptomeningeal enhancement, initially treated as neurosarcoidosis. This progressed, despite immunosuppression, and repeated lumbar punctures yielded no cerebrospinal fluid (CSF) (\u2018dry taps\u2019). Intradural biopsy identified a melanocytic neoplasm with a\n                    <jats:italic>GNA11<\/jats:italic>\n                    mutation. Fewer than 25 cases of isolated PDLM have been reported, and misdiagnosis is common. MRI typically shows T1-hyperintense leptomeningeal lesions but CSF is often non-diagnostic. Repeated failure to obtain CSF is a potential clinical clue to extensive leptomeningeal tumour infiltration. PDLM should be considered in atypical, treatment-refractory leptomeningeal disease. Recognising its characteristic imaging features and obtaining early biopsy are important to avoiding diagnostic delay.\n                  <\/jats:p>","DOI":"10.1136\/pn-2026-005238","type":"journal-article","created":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T17:20:27Z","timestamp":1787073627000},"page":"pn-2026-005238","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Primary diffuse leptomeningeal melanomatosis presenting as chronic meningitis and dense spinal plaques"],"prefix":"10.1136","author":[{"given":"Lauren","family":"Baldwin","sequence":"first","affiliation":[{"name":"Stoke Mandeville Hospital, Aylesbury, UK"},{"name":"Queen Elizabeth Hospital, Birmingham, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hadleigh","family":"Cuthbert","sequence":"additional","affiliation":[{"name":"Neurosurgery, Queen Elizabeth Hospital, Birmingham, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Satheesh","family":"Ramalingham","sequence":"additional","affiliation":[{"name":"Neuroradiology, Queen Elizabeth Hospital Birmingham, Birmingham, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lalit","family":"Pallan","sequence":"additional","affiliation":[{"name":"Oncology, Queen Elizabeth Hospital Birmingham, Birmingham, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephen","family":"Metcalfe","sequence":"additional","affiliation":[{"name":"Neurosurgery, Queen Elizabeth Hospital, Birmingham, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tom","family":"Hayton","sequence":"additional","affiliation":[{"name":"Neurology, University Hospital Birmingham, Birmingham, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,8,18]]},"reference":[{"key":"2026081810201886000_pn-2026-005238v1.1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jocn.2010.01.017"},{"key":"2026081810201886000_pn-2026-005238v1.2","doi-asserted-by":"publisher","DOI":"10.1111\/bpa.12241"},{"key":"2026081810201886000_pn-2026-005238v1.3","doi-asserted-by":"publisher","DOI":"10.1093\/neuonc\/noab106"},{"key":"2026081810201886000_pn-2026-005238v1.4","doi-asserted-by":"crossref","unstructured":"Baumgartner A , Stepien N , Mayr L , et al . Novel Insights into Diagnosis, Biology and Treatment of Primary Diffuse Leptomeningeal Melanomatosis. J Pers Med 2021;11. doi:10.3390\/jpm11040292","DOI":"10.3390\/jpm11040292"},{"key":"2026081810201886000_pn-2026-005238v1.5","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1016\/j.neurad.2011.02.007","article-title":"Neurocutaneous melanosis: follow-up and literature review","volume":"38","author":"Scattolin","year":"2011","journal-title":"J Neuroradiol"},{"key":"2026081810201886000_pn-2026-005238v1.6","doi-asserted-by":"crossref","first-page":"124127","DOI":"10.1016\/j.wneu.2025.124127","article-title":"Primary Diffuse Leptomeningeal Melanomatosis Initially Misdiagnosed as Type III Sturge-Weber Syndrome: A Case Report and Systematic Review of the Literature","volume":"199","author":"Zuo","year":"2025","journal-title":"World Neurosurg"},{"key":"2026081810201886000_pn-2026-005238v1.7","doi-asserted-by":"crossref","DOI":"10.1097\/MD.0000000000028613","article-title":"A case report of a patient with inoperable primary diffuse leptomeningeal melanomatosis treated with whole-brain radiotherapy and pembrolizumab","volume":"101","author":"Palacka","year":"2022","journal-title":"Medicine (Baltimore)"},{"key":"2026081810201886000_pn-2026-005238v1.8","doi-asserted-by":"publisher","DOI":"10.1038\/s41417-022-00437-6"},{"key":"2026081810201886000_pn-2026-005238v1.9","doi-asserted-by":"crossref","first-page":"6195","DOI":"10.3390\/cancers13246195","article-title":"Targeting Oncogenic G\u03b1q\/11 in Uveal Melanoma","volume":"13","author":"Lapadula","year":"2021","journal-title":"Cancers (Basel)"},{"key":"2026081810201886000_pn-2026-005238v1.10","doi-asserted-by":"crossref","first-page":"e576","DOI":"10.1212\/WNL.0000000000207195","article-title":"Pearls & Oy-sters: Primary Diffuse Leptomeningeal Melanocytosis: A Diagnostic Conundrum","volume":"101","author":"Selvarajan","year":"2023","journal-title":"Neurology"},{"key":"2026081810201886000_pn-2026-005238v1.11","doi-asserted-by":"crossref","DOI":"10.1097\/MD.0000000000022928","article-title":"Primary leptomeningeal melanomatosis successfully treated with PD-1 inhibitor pembrolizumab: A case report","volume":"99","author":"Misir Krpan","year":"2020","journal-title":"Medicine (Baltimore)"}],"container-title":["Practical Neurology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/pn-2026-005238","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T17:20:28Z","timestamp":1787073628000},"score":1,"resource":{"primary":{"URL":"https:\/\/pn.bmj.com\/lookup\/doi\/10.1136\/pn-2026-005238"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,18]]},"references-count":11,"alternative-id":["10.1136\/pn-2026-005238"],"URL":"https:\/\/doi.org\/10.1136\/pn-2026-005238","relation":{},"ISSN":["1474-7758","1474-7766"],"issn-type":[{"value":"1474-7758","type":"print"},{"value":"1474-7766","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,18]]}}}