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Immunophenotype of myxopapillary ependymomas
Ihab Lamzabi1, Leonidas D Arvanitis, Vijaya B Reddy
1Department of Pathology, Rush University Medical Center, Chicago, IL.
Summary
Myxopapillary ependymoma (MPE) diagnosis can be challenging due to epithelioid morphology. Immunohistochemistry reveals MPE commonly expresses CD99, CD56, and GFAP, aiding differential diagnosis.
Area of Science:
- Neuropathology
- Oncology
- Immunohistochemistry
Background:
- Myxopapillary ependymoma (MPE) is a rare, slow-growing tumor typically found in the spinal cord's lower regions.
- Epithelioid morphology in MPE can mimic metastatic carcinoma, complicating diagnosis.
- Previous immunohistochemical studies on MPE have yielded inconsistent results.
Purpose of the Study:
- To investigate the immunohistochemical profile of Myxopapillary Ependymoma (MPE).
- To clarify diagnostic markers for MPE, especially in cases with challenging morphology.
- To differentiate MPE from metastatic carcinomas using immunohistochemistry.
Main Methods:
- Retrospective review of 9 Myxopapillary Ependymoma (MPE) cases diagnosed between 2004 and 2011.
- Histologic material and clinical data were analyzed.
- Immunohistochemical staining was performed for CD99, GFAP, CD56, cytokeratins (CKAE1/AE3, CK8/18, CK7, CK5/6, CK20), D2-40, PLAP, AFP, Synaptophysin, NSE, E-cadherin, and TTF-1.
Main Results:
- All 9 MPE cases expressed CD99 and GFAP (100%).
- CD56 was positive in 89% of cases.
- Cytokeratin AE1/AE3 was focally positive in 100% of cases, potentially mimicking carcinoma.
- NSE was positive in all cases, suggesting neuroglial differentiation.
Conclusions:
- Myxopapillary ependymoma (MPE) predominantly expresses CD99, CD56, and GFAP.
- Cytokeratin positivity in MPE can be a diagnostic challenge, necessitating consideration of clinical and radiological findings.
- GFAP positivity is crucial for considering MPE in the differential diagnosis of spinal tumors with epithelioid features.
