Surgical histopathology of a filar anomaly as an additional tethering element associated with closed spinal dysraphism of primary neurulation failure
Tóm tắt
Closed spinal dysraphism of primary neurulation failure could be associated with filar anomalies, such as filar lipoma or thickened and tight filum terminale (TFT), resulting from impaired secondary neurulation. Retained medullary cord (RMC) is a remnant of the cavitary medullary cord originating from the secondary neurulation failure. Some filar lipomas are known to contain a central canal-like ependyma-lined lumen with surrounding neuroglial tissues (E-LC w/NGT), that is, a characteristic histopathology of RMC. To clarify the embryological background of these filar anomalies, we evaluated the histopathological findings.
Among 41 patients with lesions of primary neurulation failure who underwent initial untethering surgery, the filum including cord-like structure (C-LS) was additionally resected in 10 patients (five dorsal and transitional lipomas; five limited dorsal myeloschisis). We retrospectively analyzed the clinical, neuroradiological, intraoperative, and histopathological findings.
Among 10 patients, two patients were diagnosed with RMC based on morphological features and intraoperative neurophysiological monitoring. The diagnosis of filar lipoma was made in six patients, since various amounts of fibroadipose tissue were histopathologically noted in the filum. Two patients were diagnosed with TFT, since the filum was composed solely of fibrocollagenous tissue. E-LC w/NGT was noted not only in both C-LSs of RMCs but also in two out of six fila both with filar lipomas and fila with TFTs.
These findings provide further evidence for the idea that entities, such as filar lipoma, TFT, and RMC, can be considered consequences of a continuum of regression failure occurring during late secondary neurulation.
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Tài liệu tham khảo
Arai, 2001, Surgical experience of 120 patients with lumbosacral lipomas, Acta Neurochir (Wien), 143, 857, 10.1007/s007010170015
Choi, 2019, The ventriculus terminalis and filum terminate of the human spinal cord, Hum Pathol, 23, 916, 10.1016/0046-8177(92)90405-R
Durdaĝ, 2015, Pathological evaluation of the filum terminale tissue after surgical excision, Childs Nerv Syst, 31, 759, 10.1007/s00381-015-2627-4
Gupta, 2018, Fatty filum terminale (FFT) as a secondary tethering element in children with closed spinal dysraphism, Childs Nerv Syst, 34, 925, 10.1007/s00381-017-3700-y
Hashiguchi, 2005, Usefulness of constructive interference in steady-state magnetic resonance imaging in the presurgical examination for lumbosacral lipoma, J Neurosurg, 103, 537
Hiraoka, 2018, Limited dorsal myeloschisis with no extradural stalk linking to a flat skin lesion: A case report, Childs Nerv Syst, 34, 2497, 10.1007/s00381-018-3938-z
Kim, 2020, Secondary neurulation defects-1: Retained medullary cord, J Korean Neurosurg Soc, 63, 314, 10.3340/jkns.2020.0052
Kurogi, 2021, Two cases of retained medullary cord running parallel to a terminal lipoma, Surg Neurol Int, 12, 112, 10.25259/SNI_626_2020
Morioka, 2020, Congenital dermal sinus elements in each tethering stalk of coexisting thoracic limited dorsal myeloschisis and retained medullary cord, Pediatr Neurosurg, 55, 380, 10.1159/000511876
Morioka, 2020, Retained medullary cord associated with sacral subcutaneous meningocele and congenital dermal sinus, Childs Nerv Syst, 36, 423, 10.1007/s00381-019-04301-1
Morioka, 2017, Neurosurgical management and pathology of lumbosacral lipomas with tethered cord, Neuropathology, 37, 385, 10.1111/neup.12382
Morioka, 2020, Terminal syringomyelia associated with lumbar limited dorsal myeloschisis, Childs Nerv Syst, 36, 819, 10.1007/s00381-019-04297-8
Morioka, 2019, Surgical histopathology of limited dorsal myeloschisis with flat skin lesion, Childs Nerv Syst, 35, 119, 10.1007/s00381-018-3870-2
Morioka, 2018, Neurosurgical pathology of limited dorsal myeloschisis, Childs Nerv Syst, 34, 293, 10.1007/s00381-017-3625-5
Morota, 2017, New classification of spinal lipomas based on embryonic stage, J Neurosurg Pediatr, 19, 428, 10.3171/2016.10.PEDS16247
Mukae, 2020, Two cases of large filar cyst associated with terminal lipoma: Relationship with retained medullary cord, World Neurosug, 142, 294, 10.1016/j.wneu.2020.07.026
Murakami, 2013, Usefulness of three-dimensional T1-weighted spoiled gradient-recalled echo and three-dimensional heavily T2-weighted images in preoperative evaluation of spinal dysraphism, Childs Nerv Syst, 29, 1905, 10.1007/s00381-013-2140-6
Murakami, 2018, Retained medullary cord extending to a sacral subcutaneous menigocele, Childs Nerv Syst, 34, 527, 10.1007/s00381-017-3644-2
Murakami, 2018, Ependyma-lined canal with surrounding neuroglial tissues in lumboscaral lipomatous malformations: Relationship with retained medullary cord, Pediatr Neurosurg, 53, 387, 10.1159/000494029
Pang, 2020, Secondary neurulation defects-1: Thickened filum terminale, retained medullary cord, Textbook of Pediatric Neurosurgery, 1st ed, 10.1007/978-3-319-72168-2_112
Pang, 2011, Retained medullary cord in humans: Late arrest of secondary neurulation, Neurosurgery, 68, 1500, 10.1227/NEU.0b013e31820ee282
Pang, 1993, Sacral agenesis and caudal spinal cord malformations, Neurosurgery, 32, 755, 10.1227/00006123-199305000-00009
Sala, 2014, Retained medullary cord confirmed by intraoperative neurophysiological mapping, Childs Nerv Syst, 30, 1287, 10.1007/s00381-014-2372-0
Selçuki, 2003, Is a filum terminale with a normal appearance rarely normal?, Childs Nerv Syst, 19, 3, 10.1007/s00381-002-0665-1