{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T00:29:35Z","timestamp":1786494575444,"version":"build-2736575974"},"reference-count":14,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","license":[{"start":{"date-parts":[[2026,8,10]],"date-time":"2026-08-10T00:00:00Z","timestamp":1786320000000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Neurosurg Case Lessons"],"published-print":{"date-parts":[[2026,8,10]]},"abstract":"\n BACKGROUND<\/jats:title>\n Atypical neurofibromatous neoplasm of uncertain biological potential (ANNUBP) is a rare type of peripheral nerve sheath tumor that exhibits at least two of the following features: atypia, loss of neurofibroma architecture, hypercellularity, and a mitotic index of > 1 per 50 high-power fields (HPF) and < 3 per 10 HPF.<\/jats:p>\n <\/jats:sec>\n \n OBSERVATIONS<\/jats:title>\n The authors report the first case of a spinal intradural ANNUBP, the first from the Philippines, and the second in a patient without neurofibromatosis type 1 (NF1). The patient was a 50-year-old man who presented with a 1-year history of back pain and progressive bilateral lower extremity weakness and sensory loss. His motor strength was 0\/5 in both lower extremities, and the last normal sensory level was at T7. Imaging showed a T6\u20137 intradural extramedullary lesion with a contrast-enhancing rim. The patient underwent laminectomy and gross-total tumor excision, but his neurological function did not improve. Histopathological and immunohistochemical testing revealed the diagnosis of ANNUBP.<\/jats:p>\n <\/jats:sec>\n \n LESSONS<\/jats:title>\n This report describes a rare case of a spinal intradural extramedullary ANNUBP, a lesion typically located outside the CNS. This case adds to the limited body of literature on ANNUBP, emphasizing its potential to occur outside typical locations and in non-NF1 patients.<\/jats:p>\n \n https:\/\/thejns.org\/doi\/10.3171\/CASE26258<\/jats:ext-link>\n <\/jats:p>\n <\/jats:sec>","DOI":"10.3171\/case26258","type":"journal-article","created":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T00:01:22Z","timestamp":1786492882000},"source":"Crossref","is-referenced-by-count":0,"title":["Spinal intradural extramedullary atypical neurofibromatous neoplasm of uncertain biological potential: illustrative case"],"prefix":"10.3171","volume":"12","author":[{"given":"Sairon Jay B.","family":"Libit","sequence":"first","affiliation":[{"name":"Division of Neurosurgery, Department of Neurosciences, College of Medicine and Philippine General Hospital, University of the Philippines Manila"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4671-4143","authenticated-orcid":true,"given":"John Carlo B.","family":"Reyes","sequence":"additional","affiliation":[{"name":"Division of Pathology, Department of Laboratories, College of Medicine and Philippine General Hospital, University of the Philippines Manila, Manila, Philippines"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4526-6235","authenticated-orcid":true,"given":"Kathleen Joy O.","family":"Khu","sequence":"additional","affiliation":[{"name":"Division of Neurosurgery, Department of Neurosciences, College of Medicine and Philippine General Hospital, University of the Philippines Manila"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"issue":"4","key":"bib1","series-title":"Cancers (Basel)","first-page":"1077","article-title":"Malignant peripheral nerve sheath tumors: latest concepts in disease pathogenesis and clinical management","volume":"15","author":"Yao","year":"2023","unstructured":"Yao CZhou HDong YMalignant peripheral nerve sheath tumors: latest concepts in disease pathogenesis and clinical management. Cancers (Basel). 2023;15(4):1077. doi:10.3390\/cancers15041077"},{"key":"bib2","series-title":"Hum Pathol","first-page":"1","article-title":"Histopathologic evaluation of atypical neurofibromatous tumors and their transformation into malignant peripheral nerve sheath tumor in patients with neurofibromatosis type 1: a consensus overview","volume":"67","author":"Miettinen","year":"2017","unstructured":"Miettinen MMAntonescu CRFletcher CDMHistopathologic evaluation of atypical neurofibromatous tumors and their transformation into malignant peripheral nerve sheath tumor in patients with neurofibromatosis type 1: a consensus overview. 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