Thoracic metastatic posterior fossa group A ependymoma:a case report
ZOU Yu-lei
KONG Xue-ying
YANG Jie
FANG Shun
Abstract：Objective To investigate the clinical pathological characteristics, differential diagnosis, and related literature review of extracranial metastatic posterior fossa group A ependymoma. Methods A case of posterior fossa group A ependymoma with metastasis to the thoracic cavity was collected. Results The patient was a 7-year-old male who had been diagnosed with anaplastic ependymoma in the fourth ventricle for more than 4 years, and had undergone radiotherapy, chemotherapy, and adjuvant therapy. CT examination upon admission revealed multiple hypermetabolic lesions in the right lower thoracic cavity, right pleura, and mediastinal lymph nodes of group 7. Under the microscope, the tumor cells were arranged in sheets, islands, and papillary patterns, with abundant cytoplasm, eosinophilic staining, deeply stained nuclei, and fibrous stromal proliferation. Immunohistochemical results from two specimens showed GFAP positivity, EMA perinuclear dot-like positivity, and loss of H3K27Me3 expression. Conclusion Metastatic posterior fossa group A ependymoma located outside the central nervous system is extremely rare. The histological features of the metastatic lesions may not be typical. Combining the medical history, immunohistochemistry, and molecular testing can help pathologists and clinicians improve their understanding of metastatic posterior fossa group A ependymoma.
Keywords：Thoracic cavityMetastatic ependymomaPosterior fossa group A ependymomaH3K27Me3EWSR1 gene
Publication Date：2025-05-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：3( 607-609 )