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[Recurrent meningioma with malignant transformation: a case which changed from meningothelial type to papillary type]
1Department of Neurosurgery, Kitasato University School of Medicine, Kanagawa, Japan.
Abstract:
We report here a case with meningioma showing malignant transformation in its course of multiple recurrences. A 59-year-old woman developed a right-sided hemiparesis in June, 1982 and CT scan disclosed a parasagittal well-enhanced mass. The tumor was subtotally removed (Simpson grade III) by an operation in September, 1982. Histological findings of the tumor were consistent with a meningothelial meningioma but showed no malignant features, such as high cellularity, necrotic foci, high mitotic rate, or nuclear pleomorphism. However, the tumor did invade the underlying cerebral cortex. In August, 1986, a recurrent tumor was detected by CT scan and was removed (Simpson grade III). The tumor tissue at the second operation showed the same histological features as the first specimen. In September, 1990, the patient developed multiple intracranial recurrences. There were three tumor nodules, all of which were removed. Histologically, significant histological differences between the second and the third operative specimens were found. In the last tumor tissue, one nodule showed a papillary pattern. In the other tumor nodules, each tumor cell had proliferated separately instead of adhering to other tumor cells to form a syncytium. This histological pattern was consistent with an epithelial meningioma described by Cushing and Eisenhardt in 1938. The papillary portion of the tumor was stained with monoclonal antibody Ki-67 in frozen section. The labelling index was 9.7%, which was as high as malignant meningioma. Electron microscopic examination of the papillary portion of the tumor showed that the tumor cells had irregular nuclei, interdigitations between the adjacent plasma membranes and a few ill-developed desmosomes.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
This case study details a meningioma that transformed into a malignant epithelial meningioma over multiple recurrences. Histological analysis revealed distinct changes, including a papillary pattern and high Ki-67 labeling index, indicating aggressive behavior.
Area of Science:
- Neuro-oncology
- Surgical Pathology
Background:
- Meningiomas are typically benign tumors of the meninges.
- Malignant transformation of meningiomas is rare but can occur, especially after recurrence.
Observation:
- A patient with a history of meningioma experienced multiple recurrences over several years.
- Initial tumor histology was consistent with meningothelial meningioma without malignant features.
- Subsequent recurrences showed significant histological changes, including a papillary pattern and features of epithelial meningioma.
Findings:
- The recurrent tumor exhibited malignant characteristics, including a high Ki-67 labeling index (9.7%) in the papillary portion.
- Electron microscopy revealed irregular nuclei and altered cell junctions, consistent with dedifferentiation.
- The transformation from a benign to a potentially malignant meningioma was observed over time.
Implications:
- This case highlights the potential for meningiomas to undergo malignant transformation, necessitating careful monitoring of recurrent tumors.
- Understanding the histological evolution of meningiomas is crucial for accurate diagnosis and treatment planning.
- Further research into the mechanisms of meningioma dedifferentiation may lead to improved therapeutic strategies.