Brian Sorensen, MD and P-L Westesson, MD, PhD, DDS
Clinical
Presentation: A
30-year old male presented with severe low back pain after falling down the stairs. A radiograph 6 month later suggested coccygeal fracture. The pain persisted despite conservative management and an MRI was performed.
Imaging Findings: An AP view of the sacrum reveals a left lower sacral lucency representing destructive change. MRI demonstrates a large lobulated soft tissue mass arising from the left anterior sacrum and displacing the presacral colon ventrally. The mass is heterogeneous in signal, predominantly isointense to marrow on T1WI and isointense to CSF on T2WI. Signal heterogeneity may represent internal hemorrhage, proteinaceous material, and/or fibrosis. Osseous destruction of S4 and S5 vertebrae is noted. CT reveals minimal calcification and septation within the lesion.
Figure 1: AP view of the sacrum and coccyx.
Figure 2. Lateral view of the sacrum and coccyx.
Figure 3: T1-weighted sagittal image of the lumbosacral spine.
Figure 4: T2-weighted sagittal image of the lumbosacral spine.
Figure 5: T2-weighted axial image of the sacral region.
Figures 6 & 7: Axial CT biopsy images.
Diagnosis: Sacrococcygeal chordoma
Discussion: Comprising less than 1% of CNS tumors, chordomas are rare malignant neoplasms arising from ectopic extradural notochord remnants in the 5th and 6th decades of life. Following the natural distribution of remnant notochord, 49% of chordomas are found in the sacrococcygeal region, 30% in the sphenooccipital area (commonly occurring at the clivus), and 15% involve the vertebral bodies. Although slow-growing and rarely metastatic, chordomas are locally invasive and destructive. Local recurrence is common.
Clinical presentation is location dependent. Sacrococcygeal chordomas typically present with back and lower extremity pain. A sacral mass may be palpated. Autonomic dysfunction, such as urinary incontinency and rectal dysfunction, occurs in approximately 50% of cases. With intracranial chordomas, headache and diplopia are common. Palsies of cranial nerve VI and sensory branches of V and III may be seen.
The differential diagnosis for chordoma includes chondrosarcoma, giant cell tumor, metastases, multiple myeloma, and lymphoma. Sacrococcygeal teratomas should be considered in the pediatric population. Ecchordosis physaliphora, a benign mass of notochordal remnants, is usually found at the skull base.
Radiographically, chordoma presents as a heterogeneous, destructive mass which may extend into the epidural space or neural foramina. CT reveals amorphous intratumoral calcification in 70% of sacral chordomas. MRI findings include hypo/isointense signal (compared to marrow) on T1WI, hyperintensity to CSF on T2WI, and variable enhancement on contrast-enhanced T1WI. Histologically, physaliphorous cells confirm the diagnosis.
Excision is the primary mode of treatment for chordoma. Adjuvant radiotherapy has been shown to delay recurrence in the setting of subtotal resection. Chemotherapy plays no significant role in treatment of chordoma. Despite en bloc resection, local recurrence has been reported to be 28-64%. The 5-year survival after relapse is approximately 5-7%.
References:
Fourney DR and Gokaslan ZL. Current management of sacral chordoma. Neurosurg Focus. 2003 Aug 15;15(2):E9. [Medline]
Ishii K, Chiba K, Watanabe M, Yabe H, Fujimura Y, Toyama Y. Local recurrence after S2-3 sacrectomy in sacral chordoma. Report of four cases. J Neurosurg. 2002 Jul;97(1 Suppl):98-101. [Medline]
