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Rhabdoid papillary meningioma
1First Department of Pathology, Fukushima Medical University School of Medicine, Fukushima, Japan. hirohojo@fmu.ac.jp
Abstract:
We have studied an uncommon case of rhabdoid papillary meningioma in a 15-year-old boy with a dura-based mass arising in the left posterior fossa. The patient exhibited prominent extracranial extension during the past 6 years, consisting of a mixture of both perivascular pseudopapillary growth and rhabdoid cytologic features of neoplastic meningothelial cells. The meningothelial features were evidenced by the focal whorl formation of tumor cells, coexpression of epithelial membrane antigen and vimentin, and ultrastructural findings of interdigitated cytoplasmic process and intercellular junction. However, the regional and histologic resemblances to ependymoma were further complicated by unexpected focal expression of glial fibrillary acidic protein, neurofilament, and alpha-smooth muscle actin of the tumor cells. The rhabdoid morphology was characterized by sheets of tumor cells with eccentric nuclei and abundant eosinophilic cytoplasm with often recognizable intracytoplasmic hyaline inclusions. These inclusions revealed ultrastructural paranuclear whorls of intermediate filaments, ruling out the other forms of intracytoplasmic eosinophilic inclusions resembling rhabdoid morphology. Diagnosis of an unusual rhabdoid papillary meningioma with aggressive behavior is resoluble by immunohistochemical and ultrastructural analyses.
Insights
This study details an unusual rhabdoid papillary meningioma in a teenage boy, highlighting its aggressive behavior and complex cellular features. Immunohistochemical and ultrastructural analyses are crucial for diagnosing this rare brain tumor.
Area of Science:
- Neuro-oncology
- Pathology
- Pediatric Oncology
Background:
- Rhabdoid papillary meningioma is a rare and aggressive variant of meningioma.
- Accurate diagnosis is challenging due to overlapping histological features with other tumors.
Observation:
- A 15-year-old boy presented with a left posterior fossa dura-based mass with significant extracranial extension.
- The tumor displayed a mix of meningothelial, papillary, and rhabdoid cytologic features.
- Histological analysis revealed focal expression of glial fibrillary acidic protein, neurofilament, and alpha-smooth muscle actin, complicating diagnosis.
Findings:
- Meningothelial differentiation was confirmed by whorl formation and coexpression of epithelial membrane antigen and vimentin.
- Rhabdoid morphology was characterized by sheets of cells with eccentric nuclei and eosinophilic cytoplasm containing intermediate filament whorls.
- Immunohistochemical and ultrastructural analyses were essential to differentiate from other entities and confirm the diagnosis.
Implications:
- This case underscores the importance of comprehensive diagnostic techniques for rare brain tumors.
- Understanding the complex immunophenotype aids in predicting tumor behavior and guiding treatment strategies.
- Further research into the molecular basis of aggressive meningioma variants is warranted.