Tumors and Tumorlike Conditions



Tumors and Tumorlike Conditions





▪ VERTEBRAL METASTASES


KEY FACTS



  • Vertebral metastases occur in 5% to 10% of all cancer patients, especially those with primary tumors in the breast, prostate, uterus, and lung; myeloma; and lymphoma.


  • Most vertebral metastases have a combined osseous/epidural/intradural location.


  • Most vertebral metastases occur in the thoracic spine. Vertebral metastases are multiple in 90% of patients.


  • Most common symptoms from metastases include pain, weakness, autonomic dysfunction, and sensory loss.


  • Most vertebral body metastases may be screened with noncontrast sagittal T1; evaluation of epidural/intradural extension needs contrast administration; following contrast administration, many vertebral metastases become isointense to normal marrow and difficult to visualize (fat suppression may be needed in this situation). Tumor is bright on diffusion-weighted imaging (DWI) (showing low apparent diffusion coefficient [ADC]) due to hypercellularity.






FIGURE 22-1. Midsagittal T1 shows low signal in C6 and T1 from metastases. There is posterior extension of tumor at C6, resulting in cord compression.






FIGURE 22-2. Corresponding postcontrast T1 shows tumor to enhance. Note that tumor at T1 became isointense to normal bone marrow in this non-fat-suppressed image. Epidural extension at C6 is clearly seen.







FIGURE 22-3. Corresponding T2 in the same patient as 22-1 and 22-2 fat-suppressed image shows tumor deposits to be bright.






FIGURE 22-4. Midsagittal postcontrastT1 shows tumor in two midthoracic vertebrae with unusual disc involvement. Note acute kyphosis and that tumor is nearly isointense to normal enhancing bone marrow.






FIGURE 22-5. Axial post contrastT1, in the same patient shown in 22-4, shows tumor in the epidural space and “curtain” sign.






FIGURE 22-6. Axial CT (different level), in the same patient, shows mostly lytic nature of these metastases from a thyroid carcinoma.






FIGURE 22-7. Axial noncontrastT1, in a different patient, shows prominent “curtain” sign due to tumor in the anterior epidural space.






FIGURE 22-8. Midsagittal DWI, in a different patient, shows subtle high signal (arrow) from vertebral body with metastasis.



SUGGESTED READING

Cuenod CA, Laredo JD, Chevret S. et al. Acute vertebral collapse due to osteoporosis or malignancy: appearance on unenhanced and gadolinium-enhanced MR images. Radiology 1996:199:541-549.



□ SPINAL CORD AND LEPTOMENINGEAL METASTASES


KEY FACTS



  • These types of metastases occur in<1% of cancer patients, especially those with primary tumors in the lung (>50%) and breast or those with lymphoma, melanoma, colorectal carcinoma, head and neck carcinoma, and leukemia.


  • The thoracic region is most commonly involved by both types of metastases.


  • Although secondary to hematogenous dissemination, spinal cord metastases from primary CNS tumors (mainly medulloblastoma) spread via cerebrospinal fluid (CSF) pathways.


  • Tumors of the CNS that most commonly spread via CSF include medulloblastoma, ependymoma, and glioma.


  • Faint enhancement along the ventral surface of the conus medullaris may be normal vascular enhancement and should not be confused with metastases; enhancement may also occur 4 to 6 weeks after spinal or posterior fossa surgery.


  • The most common sites of leptomeningeal metastases in the spine are the lumbar, thoracic, and cervical regions.


  • Main differential diagnosis: for spinal cord lesions—primary tumors, demyelinating disease; for leptomeningeal lesions—tuberculosis, chemical meningitis, post-subarachnoid hemorrhage changes, hypertrophic polyneuropathies, Guillain-Barre.






FIGURE 22-9. MidsagittalT2 shows an extensive spinal cord bright edema due to a focal metastasis (arrow) that is dark.






FIGURE 22-10. Corresponding postcontrast T1 shows bright enhancement in the tumor.







FIGURE 22-11. Midsagittal postcontrast fat-suppressed T1, in a different patient, shows enhancement in the distal spinal cord, conus medullaris, cauda equina, and walls of distal thecal sac compatible with leptomeningeal carcinomatosis.






FIGURE 22-12. Axial postcontrast T1, in a different patient, shows thick enhancing nerve roots.






FIGURE 22-13. Axial CT post myelogram, in a different patient, shows thick matted nerve roots.






FIGURE 22-14. Midsagittal postcontrast T1, in a different patient, shows ill-defined single, large, and intradural metastasis at L1-L2 level.



SUGGESTED READING

Koeller KK, Rosenblum RS, Morrison AL. Neoplasms of the spinal cord and filum terminale: radiologic-pathologic correlation. RadioGraphics 2000;20:1721-1749.



▪ SPINAL CORD ASTROCYTOMA


KEY FACTS



  • Of spinal cord astrocytomas, >75% (in both children and adults) are low-grade histologically, and they are found more commonly in males.


  • They are the second most common primary spinal cord tumor after ependymoma.


  • Most spinal cord astrocytomas involve the cervicothoracic region.


  • Most spinal cord astrocytomas are discovered during third to fourth decades of life.


  • Early symptoms are nonspecific or nonlocalizing and include pain and scoliosis.


  • Spinal cord astrocytomas are slow growing and result in bone changes in 50% of cases.


  • Associated cysts are common (40%), and holocord involvement is not rare especially in children.


  • About 90% of spinal cord astrocytomas enhance on postcontrast magnetic resonance imaging (MRI).


  • Main differential diagnosis: ganglioglioma, ependymoma, lymphoma, transverse myelitis.






FIGURE 22-15. Midsagittal postcontrast T1 shows expansion of cervicothoracic spinal cord with patchy zones of enhancement.






FIGURE 22-16. Corresponding T2 shows high signal and cystlike areas in the expanded cord.







FIGURE 22-17. MisagittalT2, in the same patient, shows that the tumor continuous inferiorly to involve the conus medullaris.






FIGURE 22-18. Midsagittal fat-suppressed post-contrast T1, in a different patient, shows extensively enhancing cord tumor.






FIGURE 22-19. CorrespondingT2 shows that the tumor contains multiple cysts inferiorly and has a large component in the medulla.






FIGURE 22-20. Axial postcontrast T1, in the same patient, shows enhancing tumor involving the entire transverse cord diameter.



SUGGESTED READING

Pollack IF. Intramedullary spinal cord astrocytomas in children. Pediatr Blood Cancer 2004;43:617-618. Seo H-S, Kim J-H, Lee DH, Lee YH, Suh S-I, Kim SY, et al. Nonenhancing intramedullary astrocytomas and other MR imaging features: a retrospective study and systematic review. Am J Neuroradiol 2010;31:498-503.



▪ SPINAL CORD EPENDYMOMA


KEY FACTS



  • The most common (65%) primary tumor of the spinal cord; increased incidence in patients with NF-2.


  • Spinal ependymomas occur predominantly in the lower spinal cord, conus medullaris, and filum terminale (at this location it is typically of the myxopapillary subtype).


  • They are predominantly found during fifth to sixth decades of life with a slight female predominance.


  • They present with only back pain, but occasionally, patients have leg weakness and sphincter dysfunction. Occasionally, they present with superficial siderosis and even acute hemorrhage.


  • Spinal ependymomas are slow-growing lesions that may produce bone scalloping; widening of the spinal canal is seen in 30% of cases.


  • About 64% of spinal cord ependymomas have evidence of prior hemorrhage by MRI; most show well-defined margins (although occasionally they invade the conus medullaris), T2 signal is variable and may be bright or dark if calcifications and/or hemorrhage are present, and all enhance contrast administration.


  • Intratumoral cysts are more common than with astrocytomas.


  • Main differential diagnosis: intramedullary lesions— astrocytoma, ganglioglioma, lymphoma, metastasis, hemangioblastoma, transverse myelitis; conal/filum lesions— nerve sheath tumors, meningioma, astrocytoma, paraganglioma.







FIGURE 22-21. Midsagittal postcontrast T1 shows enhancing mass in the upper cervical cord and medulla. The spinal canal is slightly expanded.






FIGURE 22-22. Midsagittal postcontrast T1, in a different patient, shows typical location and shape of an ependymoma of the myxopapillary type.






FIGURE 22-23. Midsagittal postcontrast T1, in a different patient, shows small tumor in the region of distal conus.






FIGURE 22-24. Midsagittal T2, in a different patient, shows mostly bright ependymoma.






FIGURE 22-25. Axial postcontrast T1, in the same patient, shows that tumor enhances.






FIGURE 22-26. Midsagittal fat-suppressed post-contrast T1, in a different patient, shows large enhancing ependymoma and prominent veins on the spinal cord superiorly. The distal thecal sac has abnormal signal intensity due to drop metastases.






FIGURE 22-27. Corresponding T2 shows the large tumor to be mostly bright. CSF in the distal sac is also bright due to high protein content.






FIGURE 22-28. Midsagittal fat-suppressed post-contrastT1 shows a very large tumor expanding the bony canal. (Case courtesy C. Harr, Spokane, WA.)

Sep 8, 2016 | Posted by in NEUROLOGICAL IMAGING | Comments Off on Tumors and Tumorlike Conditions

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