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Atypical Teratoid/Rhabdoid Tumor ( AT/RT)of Lumbosacral Spine: Uncommon Tumor at Unusual Location 2014

Category General Spine Udaykamal Barad, MD
Ammar Taha, MD
Annette Douglas, MD
Purpose To describe imaging features, clinopathological correlation as well as surgical management of this uncommon primary spinal tumor Materials & Methods A four year old female presented with left posterior thigh worsening pain. Initially her symptoms started as frequent urinary tract infection over two month period. Her clinical course was complicated by worsening left lower extremity pain and began walking with limp. Lumbar spine MR imaging obtained at an outside hospital demonstrated a lumbosacral spinal canal mass. The patient was transferred to our facility for further evaluation, and MR imaging of the entire spine and brain was performed. Results MR imaging of spine showed large heterogeneous intradural extramedullary spinal canal mass from L5 to S3 extending through neural foramen at S1-S2 and S2-S3 into presacral space. The lesion was hypo intense to cord on T1 weighted images and predominantly T2 iso to mildly hyper intense with internal cystic areas. On post contrast images, there was heterogeneous enhancement with internal non enhancing areas. Findings of MR imaging of the brain, performed at the same time, were normal. The initial differential diagnosis based on MR findings included atypical nerve sheath tumor, primitive neuroendocrine tumor, metastasis or aggressive bone tumor such as Ewing’s sarcoma. A biopsy was performed, revealing a histopathologic diagnosis of lipoblastoma. On the basis of pathological findings, further imaging was undertaken to exclude renal mass and findings of MR abdomen were normal. On recent follow up imaging, MR spine shows persistent tumor in lumbosacral spinal canal with partial response from chemoradiation. In literature less than 10 cases of primary spine AT/RT were discovered and only one reported lumbar case was described as having intradural location. ASSR images.zip Conclusion AT/RT in the spine is very rare but can be considered in differential diagnosis of spinal canal tumors in pediatric population specifically less than five year old patients. The tumor may be intramedullary or intradural extramedullary in origin. Imaging features consistent with diagnosis include heterogeneity, iso to hypointense on T2 weighted images and intratumoral cyst. However, imaging features in spine are nonspecific but are in keeping with findings described in brain. Histology supported by immunochemistry and genetic analyses are essential in making final diagnosis. The prognosis of AT/RT occurring in the spine does not seem to differ from those occurring in the CNS. References 1. Rorke LB, Packer RJ, Biegel JA. Central nervous system atypical teratoid/rhabdoid tumor of infancy and childhood:definition of an entity. J Neurosurg 1996:85:56-65 2. Burger PC, Yu IT, Tihan T, et al. Atypical teratoid/rhabdoid tumors of the central nervous system: a highly malignant tumor of infancy and childhood frequently mistaken for medulloblastoma: a Pediatric oncology group study. Am J Surg Pathol 1988:22:1083-92 3. Cheng YC, Lirng JF, Chang FC, et al. Neuroradiological findings in atypical/teratoid rhabdoid tumor of the central nervous system. Acta Radiol 2005:1:89-96 4. Hilden JW, Watterson J, Longee DC, et al. Central nervous system atypical teratoid/rhabdoid tumor: response to intensive therapy and review of the literature. J Neurooncol 1998;40:265–75 5. Tamiya T, Nakashima H, Ono Y, et al. Spinal atypical teratoid/rhabdoid tumor in an infant. Pediatr Neurosurg 2000; 32:145–49. 6. Bambakidis NC, Robinson S, Cohen M, e al. Atypical teratoid/rhabdoid tumors of the central nervous system: clinical, radiographic and pathologic features. Pediatr Neurosurg 2002;37:64–70. 7. Rosemberg S, Menezes Y, Sousa MR, et al. Primary malignant rhabdoid tumor of the spinal dura. Clin Neuropathol 1994;13:221–24. 8. Howlett DC, King AP, Jarosz JM, et al. Imaging and pathologic features of primary malignant rhabdoid tumors of the brain and spine. Neuroradiology 1997;39:719–23.