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Pediatric Central Nervous System Tumors as Phenotypic Manifestation of Cancer Predisposition Syndromes
Published in David A. Walker, Giorgio Perilongo, Roger E. Taylor, Ian F. Pollack, Brain and Spinal Tumors of Childhood, 2020
Giorgio Perilongo, Irene Toldo, Stefano Sartori
A proper nosologic identity has been attributed to the clinical situation characterized by the presence of multiple spinal schwannomas without associated vestibular schwannomas.63,64 Schwannomatosis is largely sporadic, likely representing new mutations, but some cases of autosomal-dominant transmission have been observed. Schwannomatosis rarely occurs in children. The genetics of schwannomatosis is complex and remains incompletely understood, but recent evidence suggests that the NF2 gene is not the culprit in germline transmission of schwannomatosis. Germline involvement of the SMARCB1 gene on chromosome 22 seems to be implicated in the genesis of schwannomatosis, with many schwannomatosis patients showing an interplay of multihit mutations involving both SMARCB1 and NF2 in affected somatic tissues. SMARCB1 has been shown to play a role in the tumorigenesis of schwannomatosis but not in isolated sporadic schwannomas. For the sake of completeness it should be noted that multiple schwannomas have been described in at least two other syndromes: the Carney complex and an unnamed constellation of schwannomas, vaginal leiomyomas, and multiple congenital nevi.6
Schwannomatosis
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
Schwannomatosis is a rare form of neurofibromatosis characterized by the formation of multiple, often painful, schwannomas in the peripheral nervous system. Despite its shared phenotypic features with NF2, schwannomatosis is a distinct clinical entity. While vestibular schwannoma is absent in familial schwannomatosis, unilateral vestibular schwannoma may sometimes be observed. This makes the use of molecular testing techniques extremely valuable in order to achieve a definitive diagnosis of schwannomatosis. Given our limited understanding of schwannomatosis and NF2 in relation to their genetics, pathogenesis, clinical presentation, and outcome, further studies are necessary to improve the detection of additional predisposing, or modifying, genes, the determination of cellular pathways, genotype/phenotype correlations, and the design of novel therapies based on affected pathways [33]. As schwannomatosis tumors survive only a few passages before senescence, the recent establishment of immortalized Schwann cell lines from human tumors provides an impetus for advancing schwannomatosis research [34,35].
Schwannoma of the external auditory canal as a part of schwannomatosis
Published in Acta Oto-Laryngologica Case Reports, 2019
Saeko Matsuzaki, Naoki Oishi, Satoko Wakabayashi, Kaoru Ogawa
Schwannomatosis is a very rare disease and seen in one out of 40,000 to 100,000 births [7]. Since around 1997, the diagnostic criteria of schwannomatosis have been proposed, and the new criteria were proposed at the 2011 international Schwannomatosis Workshop [10]. In them, the criteria for molecular diagnosis and clinical diagnosis were presented (Table 1), and responsible genes were identified, as well as three following clinical diagnostic criteria were proposed:‘Two or more non-intradermal schwannomas, at least one with pathological confirmation, including no bilateral vestibular schwannomas by MRI (Note that some NF2 patients will be included in this diagnosis at a young age and that some schwannomatosis patients have been reported to have unilateral vestibular schwannomas or multiple).’‘One pathologically confirmed schwannoma or intracranial meningioma and affected first-degree relative.’‘Consider as possible diagnosis if there are two or more non-intradermal tumors but none has been pathologically proven to be a schwannoma; the occurrence of chronic pain in association with the tumor(s) increases the likelihood of schwannomatosis.’ Patients fulfilling diagnosis for NF2 are not included in the concept of schwannomatosis.
Schwannomatosis of the sciatic nerve: a case report
Published in British Journal of Neurosurgery, 2023
Furkan Erdoğan, Ferhat Say, Yakup Sancar Barış
Schwannomatosis is a disease characterized by the development of multiple benign lesions from Schwann cells, and affecting single or multiple nerves. Schwannomatosis, which is a relatively new condition that has been described in the last few decades, is clinically and genetically considered to be a third form of neurofibromatosis, along with neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2).1,2