Clinical
Presentation: Patient is a
19-year-old right-handed male with right hand numbness and clumsiness.
Imaging Findings:
Figure 1: Sagittal T2 image shows a hyperintense intramedullary lesion expanding the cord at the C1-C3 level. A lobulated T2 hyperintense cystic lobulated component is seen inferiorly. More inferior to this there is abnormal increase T2 signal within the cord at the C5 level.
Figures 2A&B: Sagittal T1 pre- and post-contrast images show that the lesion is slightly hypointense to the normal cord before contrast administration. Following contrast administration, the lesion shows slight heterogeneous enhancement, with the T1 hypointense non-enhancing cystic component more inferiorly.
Figure 3. Axial T2 image at the level of C2 again shows the hyperintense intramedullary lesion expanding the cord, with little CSF space around the cord itself.
Figure 4: Axial GRE image at the same level shows the lesion to be slightly hyperintense with no evidence of blooming to suggest a hemorrhagic component.
Diagnosis: Malignant glioneuronal tumor of the cervical spine
Discussion: Malignant glioneuronal tumors (MGNT's) are rare CNS neoplasms that are defined by their immunohistochemical staining. These comprise two entities: anaplastic gangliomas and "rosetted glioneuronal tumors." MGNT's may occur de novo or undergo malignant degeneration from from low-grade glioneuronal tumors. In a series of 40 cases, Varlet et al. reported that in order to correctly identify these lesions, neurofilament protein (NFP) immunostaining is necessary [1]. In this series, all tumors also coexpressed glial fibrillary acidic protein (GFAP). Other neuronal markers including synaptophysin, NeuN, and chromogranin were variably expressed. In that series, 39 of the tumors were supratentorial. The remaining tumor was in the cerebellum.
There are few cases of spinal cord neuroglional tumors reported in the literature. In one case [2], the tumor showed "rosetted" neuropil islands histologically, and similar findings were found in this case. Incidentally this tumor was strongly positive for NFP, GFAP positive in the majority of tumor cells, slightly Ki-67 positive in up to half, strongly synaptophysin positive in the neuropil appearing area.
According, Varlet et al., correctly identifying MGNT's is important to neurosurgeons because total resection can be curative in some cases. These tumors can metastasize and may not recur at the primary site.
When supratentorial, these tumors tend to occur in the temporal lobe. They can have a variable imaging appearance, but some features are characteristic. The enhancing tumor can be indistinguishable from the dura. There may be T2 hypointensity surrounding the tumor, with relatively little peritumoral edema. They also may be multicentric. These features should raise the suspicion for MGNT.
References:
Varlet P, Soni D, Miquel C, Roux FX, Meder JF, Chneiweiss H, Daumas-Duport C: New variants of malignant glioneuronal tumors: a clinicopathological study of 40 cases. Neurosurgery. 2004 Dec;55(6):1377-91: discussion 1391-2. [Medline]
Harris BT Horoupian DS. Spinal cord glioneuronal tumor with "rosetted" neuropil islands and meningeal dissemination: a case report. Acta Neuropathol (Berl). 2000 Nov;100(5):575-9. [Medline]
Sharma S, Sarkar C, Gaikwad S, Suri A, Sharma MC. Primary neurocytoma of the spinal cord: a case report and review of literature. J Neurooncol. 2005 Aug;74(1):47-52. [Medline]
