Presentation
18 months of neck pain radiating down to right arm.
Patient Data
There is a 9 x 11 x 20 mm intramedullary mass in the upper cervical spinal cord. It is centrally located and extends between C2/3 and mid C4 levels. Associated cord expansion is noted.
Pre-contrast, the mass shows heterogeneous high T2 signal and T1 signal slightly less than that of spinal cord. There is an associated tumor syrinx extending between C1/2 and the lower C4 vertebral levels (37 mm craniocaudally), at the inferior aspect of which there is low T2 signal compatible with a "hemosiderin cap". The mass shows avid, homogeneous enhancement.
The remainder of the cervical spinal cord is normal in signal and caliber. The cervico-medullary junction is normally positioned. Posterior disc-osteophyte complexes at C5/6, C6/7, and C7/T1 mildly narrow the central vertebral canal. The neural exit foramina are adequate.
Vividly enhancing intramedullary mass ( * ) is located centrally within the cord (note the cord evenly splayed around mass on axial imaging (blue arrows) ) with a prominent inferior hemosiderin cap (yellow arrow).
The patient went on to have a laminectomy and excision of the tumor.
Histology
MICROSCOPIC DESCRIPTION: Sections show a moderately cellular glial tumor. The tumor comprises a mixed population of cells, some showing glial features with fibrillary processes, yet others displaying more epithelioid features. There is a prominent population of cells showing signet ring cell like features. Many perivascular pseudorosettes are seen. No mitotic figures are identified and there is no necrosis or endothelial cell hyperplasia.
The tumor cells are strongly GFAP positive, show punctate dot like cytoplasmic staining for EMA, and membranous staining for CD99. The Ki-67 proliferative index is less than 1%.
FINAL DIAGNOSIS: The morphological and immunohistochemical features are of ependymoma (WHO Grade II)
Case Discussion
This case illustrates typical and characteristic appearances of an ependymoma with prominent hemosiderin capping.