Spinal cord ependymomas and myxopapillary ependymomas in the first 2 decades of life: a clinicopathological and immunohistochemical characterization of 19 cases.
OBJECTIVE
Primary spinal cord ependymomas (EPNs) are rare in children, comprising classical WHO Grade II and III tumors and Grade I myxopapillary ependymomas (MEPNs). Despite their benign histology, recurrences and neural-axis dissemination have been reported in up to 33% MEPNs in the pediatric population. Treatment options beyond resection are limited, and little is known about their tumorigenesis. The purpose of this study was to explore the tumor biology and outcomes in a consecutive series of pediatric patients treated at a single institution.


METHODS
The authors performed a retrospective clinicopathological review of 19 patients at a tertiary referral children's hospital for resection of a spinal cord ependymoma. The population included 8 patients with a pathological diagnosis of MEPN and 11 patients with a pathological diagnosis of spinal EPN (10 cases were Grade II and 1 case was Grade III). The upregulation of the following genes HOXB13, NEFL, PDGFRα, EGFR, EPHB3, AQP1, and JAGGED 1 was studied by immunohistochemistry from archived paraffin-embedded tumor samples of the entire cohort to compare the expression in MEPN versus EPN.


RESULTS
Gross-total resection was achieved in 75% of patients presenting with MEPNs and in 100% of those with EPNs. The average follow-up period was 79 months for the MEPN subset and 53 months for Grade II/III EPNs. Overall survival for both subsets was 100%. However, event-free survival was only 50% for patients with MEPNs. Of note, in all cases involving MEPNs that recurred, the patients had undergone gross-total resection on initial surgery. In contrast, there were no tumor recurrences in patients with EPNs. Immunohistochemistry revealed no significant differences in protein expression between the two tumor types with the exception of EPHB3, which demonstrates a tendency to be positive in MEPNs (6 reactive tumors of 9) rather than in EPN (2 reactive tumors of 10).


CONCLUSIONS
The authors' experience shows that, following a gross-total resection, MEPNs are more likely to recur than their higher-grade counterpart, EPNs. This supports the recommendation for close long-term radiological follow-up of pediatric patients with MEPNs to monitor for recurrence, despite the tumor's low-grade histological feature. No significant difference in the protein expression of HOXB13, NEFL, PDGFRα, EGFR, EPHB3, AQP1, and JAGGED 1 was present in this selected cohort of pediatric patients.
Divisions of Neurosurgery, Children’s Hospital of Philadelphia, PA, USA.
James H
JH
Stephen
Angela J
AJ
Sievert
Peter J
PJ
Madsen
Alexander R
AR
Judkins
Adam C
AC
Resnick
Phillip B
PB
Storm
Elisabeth J
EJ
Rushing
Mariarita
M
Santi
D000293:Adolescent; D051398:Aquaporin 1 / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002648:Child; D015331:Cohort Studies; D004806:Ependymoma / Q000378:metabolism* / Q000473:pathology*; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D000072100:Jagged-1 Protein; D008279:Magnetic Resonance Imaging; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D016900:Neurofilament Proteins / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D036223:Receptor, EphB3 / Q000378:metabolism; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000378:metabolism; D012189:Retrospective Studies; D000072099:Serrate-Jagged Proteins; D013116:Spinal Cord / Q000378:metabolism* / Q000473:pathology*; D013120:Spinal Cord Neoplasms / Q000378:metabolism* / Q000473:pathology*
D002135:Calcium-Binding Proteins; C484414:HOXB13 protein, human; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; C000606273:JAG1 protein, human; D000072100:Jagged-1 Protein; D008565:Membrane Proteins; D016900:Neurofilament Proteins; D011506:Proteins; D000072099:Serrate-Jagged Proteins; C044882:neurofilament protein L; D051398:Aquaporin 1; D066246:ErbB Receptors; D036223:Receptor, EphB3; D020796:Receptor, Platelet-Derived Growth Factor alpha