Brainstem intraparenchymal schwannoma with genetic analysis: a case report and literature review

• Published in: BMC medical genomics 2021-08, Vol.14 (1), p.205-8, Article 205
• Main Authors: Ishigami, Daiichiro, Miyawaki, Satoru, Nakatomi, Hirofumi, Takayanagi, Shunsaku, Teranishi, Yu, Ohara, Kenta, Hongo, Hiroki, Dofuku, Shogo, Kin, Taichi, Abe, Hiroyuki, Mitsui, Jun, Komura, Daisuke, Katoh, Hiroto, Ishikawa, Shumpei, Saito, Nobuhito
• Format: Article
• Language: English
• Subjects: Ataxia; Bar codes; Brain cancer; Brain stem; Brain Stem - diagnostic imaging; Brain Stem - pathology; Brain Stem Neoplasms - diagnostic imaging; Brain Stem Neoplasms - genetics; Brain Stem Neoplasms - pathology; Brain tumors; Case Report; Case reports; Case studies; Cloning; Cysts; Diagnosis; Dysphagia; Genetic analysis; Genetic aspects; Genetics; Genomes; Health aspects; Humans; Hydrocephalus; Intraparenchymal schwannoma; Labeling; Literature reviews; Magnetic resonance imaging; Male; Medical research; Myelin; Neurilemmoma - diagnostic imaging; Neurilemmoma - genetics; Neurilemmoma - pathology; Neurofibromin 2; Neuroimaging; Oncology; Ostomy; Parenchyma; Paresis; Pathology; Peripheral nerves; Radiation therapy; Schwann cells; Surgery; Tumors; Young Adult
• ISSN: 1755-8794; 1755-8794
• DOI: 10.1186/s12920-021-01049-z

Schwannomas are neoplasms that typically arise from the myelin sheath of peripheral nerves and rarely originate within the brain parenchyma. Some case reports present schwannomas arising from the brainstem, but regrowth of the tumor and the efficacy of postoperative irradiation have not been examined. In addition, the genetic background of schwannomas arising from the brainstem has not been investigated. A 21-year-old male presented with diplopia, dysphagia, and left-sided hemiparesis, dysesthesia, and ataxia. Intracranial imaging showed a heterogeneous mass with a cystic lesion in the pontomedullary junction. Since the tumor caused obstructive hydrocephalus, the patient underwent subtotal tumor resection. A histopathologic evaluation aided a diagnosis of brainstem intraparenchymal schwannoma. Gradual postoperative mass regrowth was recognized. Three-dimensional conformal radiotherapy was performed on the residual mass and surgical cavity. No tumor regrowth was observed 4 years after surgery. To investigate the genetic background of the tumor, target sequences for 36 genes, including NF2, SMARCB1, and LZTR1, and microsatellite analysis for loss of 22q did not show any somatic variants or 22q loss. We suggest that brainstem schwannomas might differ from conventional schwannomas in their genetic background.