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Exophytic Midline Spinal Cord Hamartoma 2014

Category General Spine Gary X. Gong, MD, PhD
Marty Auster, MD
Purpose The myriad of congenital spinal cord masses more commonly seen include lipomas, epidermoids, dermoids, and teratomas, etc. Congenital midline spinal hamartomas are relatively unknown with only 16 cases reported. They are composed of mature and well-differentiated histological components which are in an abnormal location/configuration. Correct diagnosis can be made by their MRI characteristics with appropriate MR imaging. After reviewing this exhibit, the radiologist will gain an understanding of typical MRI findings, possible embryogenesis, clinical features and management of this entity. Materials & Methods MRI imaging of the cervical spine with literature reports and imaging features reviewed. Results On MR imaging, these lesions demonstrate isointensity with the adjacent spinal cord parenchyma on all MRI sequences. They are mostly peg-like appearing tissue broadly based on the dorsal midline spinal cord parenchyma with a pointed narrow end inferiorly, possibly due to tethering of the cord. They may show a dermal sinus tract with vascularity that tethers the cord at the level of the lesions. Adequate MRI sequences should include precontrast routine axial and sagittal T1- and T2-weight images with thin sections through the lesion. Post contrast fat saturation sequence images may also be obtained for differential diagnosis. The differential diagnosis is straightforward from other spinal masses on the basis of MRI findings. Teratomas are characterized by heterogeneous signal and by contrast enhancement. Most dermoids have a signal intensity similar to fluid on both T1- and T2-weighted images. Most dermoids are T1 bright and appear similar to intraspinal lipoma. Surgical consultation is recommended for clinical management with possible intervention to prevent neurological damge resulting from tethering of the cord in young patient, to prevent infection of the dermal sinuses, or to correct focal cosmetic defect. Conclusion Midline spinal cord hamartoma is a distinct entity. Those hamartomas are rarely described in literatures in the past but they are likely being increasingly encountered due to wide availability of MR imaging. Most of the patients are asymptomatic or only have minimal neurological deficits. MRI features allow one to distinguish them from other intraspinal masses. Through case review, the characteristic MRI findings are illustrated. References 1. Davidson L, Gonzalez-Gomez I, McComb JG. Thoracic spinal cord tethering resulting from an exophytic hamartoma. Pediatr Neurosurg. 2009;45(3):244-6. 2. Perrini P, Scollato A, Guidi E, Benedetto N, Buccoliero AM, Di Lorenzo N. Tethered cervical spinal cord due to a hamartomatous stalk in a young adult. Case report. J Neurosurg. 2005 Mar;102(2 Suppl):244-7. 3. Riley K, Palmer CA, Oser AB, Paramore CG. Spinal cord hamartoma: case report. Neurosurgery. 1999 May;44(5):1125-7; discussion 1127-8. 4. Bining HJ, Saigal G, Goswami RS, Gill D, McNeely PD. Spinal hamartoma in a neonate: Unusual presentation and MR imaging findings. AJNR Am J Neuroradiol. 2006 Apr;27(4):810-2. 5. Takeyama J, Hayashi T, Saito M, Shimanuki Y, Watanabe M, Sasano H, Shirane R. Spinal hamartoma associated with spinal dysraphism. Childs Nerv Syst. 2006 Sep;22(9):1098-102. 6. Castillo M, Smith MM, Armao D. Midline spinal cord hamartomas: MR imaging features of two patients. AJNR Am J Neuroradiol. 1999 Jun-Jul;20(6):1169-71.