{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,28]],"date-time":"2026-07-28T04:59:54Z","timestamp":1785214794836,"version":"3.55.0"},"reference-count":14,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,7,24]],"date-time":"2026-07-24T00:00:00Z","timestamp":1784851200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vet. Sci.","Veterinary Sciences"],"abstract":"<jats:p>A 2-year-old spayed female Bichon Frise presented with progressive neurologic deterioration despite 12 months of medical management for caudal occipital malformation syndrome (CM)-associated syringomyelia (SM) and ventriculomegaly. Repeat magnetic resonance imaging (MRI) performed prior to surgical intervention demonstrated persistent CM-associated structural abnormalities together with multifocal intra-axial lesions involving the bilateral thalami, frontal white matter, and medulla that were considered most compatible with a presumptive inflammatory meningoencephalitic process, with MUO regarded as the leading differential diagnosis. Combined surgical decompression and immunosuppressive therapy using leflunomide and mycophenolate mofetil were subsequently initiated. Progressive clinical improvement followed by long-term neurological stability was observed during the approximately 2-year follow-up period. However, because both interventions were initiated concurrently, the relative contribution of each treatment to the observed clinical outcome could not be determined. No recurrence or progression of neurological signs was observed during the approximately 2-year follow-up period. This case highlights the importance of repeat MRI evaluation in neurologic patients exhibiting progressive deterioration despite previous treatment, even when an established structural diagnosis is present. Recognition of MRI findings suggestive of concurrent inflammatory disease may substantially influence diagnostic interpretation and therapeutic decision-making in selected patients.<\/jats:p>","DOI":"10.3390\/vetsci13080736","type":"journal-article","created":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T11:54:26Z","timestamp":1785153266000},"page":"736","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Concurrent Caudal Occipital Malformation Syndrome-Associated Syringomyelia and Presumptive Meningoencephalomyelitis of Unknown Origin Managed with Combined Surgical Decompression and Immunosuppressive Therapy in a Dog"],"prefix":"10.3390","volume":"13","author":[{"given":"Sung Su","family":"Park","sequence":"first","affiliation":[{"name":"IU Animal Medical Center, Seongnam-si 13646, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"469","DOI":"10.1111\/j.1939-1676.2006.tb02884.x","article-title":"Syringomyelia: Current concepts in pathogenesis, diagnosis, and treatment","volume":"20","author":"Rusbridge","year":"2006","journal-title":"J. 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Pract."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/j.tvjl.2018.12.007","article-title":"Clinical presentation, diagnostic findings, prognostic factors, treatment and outcome in dogs with meningoencephalomyelitis of unknown origin: A review","volume":"244","author":"Cornelis","year":"2019","journal-title":"Vet. J."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Jeffery, N.D., and Granger, N. (2023). New insights into the treatment of meningoencephalomyelitis of unknown origin since 2009: A review of 671 cases. Front. Vet. Sci., 10.","DOI":"10.3389\/fvets.2023.1114798"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Park, S.S. (2026). Case Report: Complete MRI-confirmed remission of presumptive meningoencephalitis of unknown origin in a Chihuahua using a steroid-free combination of leflunomide and mycophenolate mofetil. Front. Vet. Sci., 13.","DOI":"10.3389\/fvets.2026.1750629"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"e70086","DOI":"10.1111\/jvim.70086","article-title":"Evolution of brain magnetic resonance imaging lesions in dogs treated for meningoencephalomyelitis of unknown origin between initial diagnosis and relapse","volume":"39","author":"Blond","year":"2025","journal-title":"J. Vet. Intern. Med."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2204","DOI":"10.1111\/jvim.17109","article-title":"Survival in dogs with meningoencephalomyelitis of unknown etiology with and without lesions detected by magnetic resonance imaging","volume":"38","author":"Ostrager","year":"2024","journal-title":"J. Vet. Intern. Med."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Knowler, S.P., Galea, G.L., and Rusbridge, C. (2018). Morphogenesis of canine Chiari malformation and secondary syringomyelia: Disorders of cerebrospinal fluid circulation. Front. Vet. 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