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Ultrastructural examination is essential for diagnosis of papillary meningioma
S Al-Sarraj1, A King, A J Martin
1Department of Neuropathology, Neuroscience Centre, King's College Hospital, Institute of Psychiatry, London, UK. S.AI-Sarraj@iop.kcl.ac.uk
Aims:
Papillary meningioma is a rare meningeal tumour. To date only a few cases have been reported and their immunohistochemical features have not been fully documented.
Methods And Results:
A 49-year-old woman presented with a 2-month history of headaches and memory disturbance. CT and MRI imaging showed an enhancing pineal mass with extension into the occipital lobes and invasion of the splenium. At surgery, the tumour was found to be tough and vascular with a well-defined capsule. No recurrence was noted 19 months after the operation. In another case a 44-year-old woman was admitted with 1-month history of headaches, poor memory, imbalance and diplopia. CT scan showed a large hyperdense, uniformly, enhancing mass within the middle cranial fossa at the petrous ridge. The tumour recurred 19 and 25 months after first resection. The histology of both tumours was similar. The neoplasms contained polygonal cells with a moderate amount of cytoplasm, rounded regular nuclei and distinct cell borders. The cells were arranged radially around the blood vessels (perivascular pattern) and a papillary pattern was seen only focally. Mitotic figures were moderately frequent. Immunohistochemistry showed that both tumours were immunoreactive to vimentin and NSE, whereas GFAP, CAM5.2, EMA, S100 protein and synaptophysin were negative. Electron microscopy revealed interdigitating cell processes, desmosomes and intermediate filaments.
Conclusions:
The histological and immunohistochemical features of these two tumours are complex and difficult to interpret. Although papillary meningiomas were considered in our initial differential diagnosis, the final conclusion was possible only when the ultrastructural features were revealed.
Insights
This study details two rare cases of papillary meningioma, a type of brain tumor. Electron microscopy was crucial for accurate diagnosis due to complex histological and immunohistochemical features.
Area of Science:
- Neuro-oncology
- Pathology
- Neurosurgery
Background:
- Papillary meningioma is a rare meningeal tumor with limited documented immunohistochemical features.
- Accurate diagnosis is challenging due to complex histological presentations.
Observation:
- Two cases of papillary meningioma are presented: one in the pineal region and another in the middle cranial fossa.
- Clinical presentations included headaches, memory disturbance, imbalance, and diplopia.
- Tumor imaging revealed enhancing masses with invasion in one case.
Findings:
- Histologically, tumors showed polygonal cells with perivascular and focal papillary patterns.
- Immunohistochemistry revealed reactivity to vimentin and NSE, with negativity for GFAP, CAM5.2, EMA, S100, and synaptophysin.
- Electron microscopy identified interdigitating cell processes, desmosomes, and intermediate filaments, aiding definitive diagnosis.
Implications:
- Ultrastructural analysis is essential for the definitive diagnosis of challenging meningioma cases.
- Understanding the immunohistochemical profile aids in differentiating papillary meningioma from other neoplasms.
- Further research on rare meningioma subtypes is needed to improve diagnostic accuracy and patient management.