Spontaneous resolution of a Chiari malformation Type I and syrinx after supratentorial craniotomy for excision of a cavernous malformation

Case report

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The pathogenesis of Chiari malformation Type I (CM-I) and associated syringomyelia is incompletely understood. Patients often present in middle age with incidental or minimally symptomatic CM-I, whose management is controversial. One option is clinical and radiographic observation of asymptomatic and minimally symptomatic patients. The authors here present the case of a 36-year-old woman who had been monitored for 6 years for a minimally symptomatic CM-I and cervicothoracic syrinx. After 5 years of follow-up, she suffered spontaneous rupture of a cerebral cavernous malformation when she was 27 weeks pregnant. The ruptured cavernous malformation and hematoma were operatively managed via a right frontal craniotomy. Ten months after the craniotomy for resection of the ruptured cavernous malformation, follow-up MRI demonstrated resolution of the CM-I and syrinx. Few similar cases have been reported in adults. This case argues for the presence of dynamic factors in the development and maintenance of CM-I and supports the nonoperative treatment of asymptomatic and minimally symptomatic patients.

Abbreviations used in this paper:CM-I = Chiari malformation Type I; CTA = CT angiography; MRA = MR angiography.

Article Information

Address correspondence to: Carl B. Heilman, M.D., Department of Neurosurgery, Tufts Medical Center and Tufts University School of Medicine, 800 Washington Street, #178, Boston, Massachusetts 20111. email: cheilman@tuftsmedicalcenter.org.

Please include this information when citing this paper: published online February 10, 2012; DOI: 10.3171/2012.1.JNS11580.

© AANS, except where prohibited by US copyright law.



  • View in gallery

    Images are shown in the plane of maximal cerebellar tonsil ectopia. Initial sagittal T2-weighted MR image (A) obtained in September 2004, showing 14 mm of cerebellar tonsillar herniation through the foramen magnum. Also visualized are the hallmark features of CM-I: tonsillar ectopia, impaction of cerebellar tissue in the foramen magnum, and cervicomedullary kinking. Follow-up sagittal T2-weighted MR images obtained 8 months (B), 21 months (C), 3 years (D), and 4 years (E) after initial presentation, demonstrating a stable degree of tonsillar herniation ranging from 12 to 15 mm below the foramen magnum. Sagittal reconstruction of brain MRA source image (F) obtained on November 3, 2009, showing 14 mm of cerebellar tonsillar herniation below the foramen magnum. Sagittal T1-weighted brain MR images obtained on the 1st (G) and 2nd (H) days after the right frontal hemorrhage, demonstrating 13 and 16 mm of tonsillar herniation, respectively. Sagittal T1-weighted MR image (I) obtained on postoperative Day 3, showing 14 mm of tonsillar herniation. Sagittal T1-weighted MR images (J and K) obtained 2 and 6 months postoperatively, showing significant improvement in the extent of the CM-I, with 8 mm of maximal cerebellar tonsillar herniation. Cervical T2-weighted MR image (L) obtained in September 2010, showing a normal position of the cerebellar tonsils in relation to the foramen magnum.

  • View in gallery

    Axial (left) and coronal (right) T2-weighted MR images obtained after the onset of left hand and facial paresthesia and left central pattern facial paresis, showing a 3 × 3 × 3.5–cm right frontal hematoma deep to the left motor strip. No abnormality was present on unenhanced brain MRI in September 2004. Following evacuation, gross and histopathological specimens demonstrated an organizing hematoma and a small cerebral cavernous malformation.

  • View in gallery

    Sagittal (upper) and axial (lower) views of the syrinx centered at T1–2, obtained at the plane of maximal dimension. Initial image (A) obtained in September 2004, showing a syrinx measuring 28 mm in length, 6.4 mm in the lateral aspect, and 5.6 mm in the anteroposterior dimension. Annual follow-up images demonstrating a stable appearance of the syrinx at 8 months (B), 21 months (C), 3 years (D), and 4 years (E) after initial presentation. No imaging of the cervicothoracic spine was available between the 4-year follow-up spinal MRI study and 10 months after the right frontal hemorrhage (September 2010). First follow-up spine MR image (F) obtained after the hemorrhage, demonstrating near-complete resolution of the fluid cavity, with a residual fluid cavity eccentric to the right measuring 2.2 mm lateral and 2.2 mm in the anteroposterior dimension.



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