Imaging features of spinal atypical teratoid rhabdoid tumors in children

Abstract

This study aims to analyze and summarize the imaging features of spinal atypical teratoid/rhabdoid tumors (AT/RT) in children.Imaging features in 8 children with spinal AT/RT confirmed by surgical pathology were retrospectively analyzed. All patients had underwent total spine 3.0 T magnetic resonance imaging (MRI) and 64-slice spiral computed tomography (CT). Among these 8 patients, head MR non-enhanced and spinal enhanced scanning was applied to 5 patients, while CT examination was applied to 3 patients.All 8 patients were characterized by cauda equina syndrome. The lesions of 7 patients were in the thoracolumbar spinal junction, while the lesion of the remaining patient was in the lumbar spine. Furthermore, among these patients, the lesions of 5 patients were limited to the intraspinal canal (1 lesion in the epidural space, and 4 lesions in the subdural space), while the lesions of 3 patients invaded the paravertebra (2 lesions in the epidural space and 1 lesion in the subdural space). Three or more spinal segments were invaded by tumors in 7 patients, while sacral canal was affected in 5 patients. All 8 patients experienced bleeding in the tumors. Enhanced MRI revealed meningeal enhancement in 6 patients, and bilateral nerve root enhancement in 4 patients. The masses in 3 patients brought damages to the intervertebral foramen or sacral pore. The lesion of 1 patient was featured by skip growth. One patient had total spinal metastasis and 3 had hydrocephalus. The masses in 2 patients had a slightly low density when detected by CT, and enhanced scanning revealed a mild to moderate enhancement.Spinal AR/TR had the following characteristics: children were characterized by cauda equina syndrome; the mass that invaded the thoracolumbar spinal junction and the extramedullary space of multiple segments grew along the spinal longitudinal axis; bleeding mass was revealed in MRI imaging; meninges, nerve root, and sacral canal metastases occurred. The gold standard for the definite diagnosis of AT/RT is biopsy combined with immunohistochemistry.

Figure 1

AT/RT in multiple of the cervical and lumbar segments of spinal cord. A: T1WI reveals isointensive signals in the nodules of the lateral cervical medulla. B: T2WI reveals slightly higher signals, hemosiderin ring is observed around it. C: Enhanced MRI scan reveals obvious enhancement, nodular enhancement in the T6–8 segments of spinal cord (white arrow). D: CT reveals slightly higher density (white arrow). E: T11-L1 and the sacrum are fully filled with tumors. Enhanced scan reveals that the spinal meninges are obviously enhanced (arrowhead). Figures F–G: Under the microscope the tumor tissues are varies in shape, the tumor cells are diffused and arranged in pieces, and part of the cells seem like rhabdoid cells. AT/RT = atypical teratoid/rhabdoid tumors, CT = computed tomography, MRI = magnetic resonance imaging.

Figure 2

The paravertebral AT/RT affects the spinal canal, which recurs after treatment (surgical resection and radiotherapy). A: Lateral spinal soft tissue mass in right renal hilum, non-enhanced CT scan reveals isointensity. B: Enhanced CT scan coronal image reveals that masses are slightly unevenly enhanced. Masses destroy the intervertebral foramen and affect the epidural space, the spinal cord is obviously compressed. C, D, and E present upper abdominal axial enhanced MRI images at 12 months, 14 months, and 18 months after postoperative chemotherapy (ICE + CAV), respectively, it can be seen that some of masses in the original operation sites gradually grow (white diamond). AT/RT = atypical teratoid/rhabdoid tumors, CT = computed tomography, MRI = magnetic resonance imaging.

Figure 3

T10-L1 vertebral AT/RT and supratentorial cerebral ventricular system dilation. A: Sagittal T1WI reveals that the T10-L1 vertebrae present with horizontal and oval space occupying, T1WI reveals mixed slightly higher signals, patchy, and striped bleeding (white triangle) are observed. The sacral canal is fully filled with soft tissue shadows (white star). B: Sagittal T2WI reveals that lesions present with mixed slightly higher signals. C: Sagittal enhanced scanning reveals that, the tumor is slightly enhanced, linear enhancement (white arrow) can be observed in the spinal meninges. D: Head enhanced MRI reveals that, bilateral lateral ventricles are dilated. E: Immunohistochemical staining for INI-1 reveals that, the expression of INI-1 is positive in the nucleus of the vascular endothelial cells in the tumor (red pointer), and negative in the nucleus of surrounding tumor cells. AT/RT = atypical teratoid/rhabdoid tumors, MRI = magnetic resonance imaging.

Figure 4

Spinal AT/RT with whole spinal cord and whole brain diffuse metastases. A: Sagittal enhanced MRI scan reveals obvious diffuse nodular enhancement of the cervical and thoracic spinal cord. B: Enhanced scan reveals that tumors are fully filled in the sacral canal and are obviously enhanced. C: Craniocerebral axial enhanced scan reveals diffuse thickening and obvious enhancement of the meninges, nodular metastases of the right cerebellar hemisphere, and right temporal arachnoid cyst (white single diamond). AT/RT = atypical teratoid/rhabdoid tumors, MRI = magnetic resonance imaging.