Abstract
Background : We report herein on a case of microcystic meningioma with prominent nuclear-size variation and hyperchromasia superficially mimicking an anaplastic meningioma.
Case : A 77-year-old male suffered from a seizure and a subsequent magnetic resonance imaging study revealed a well-circumscribed tumor of the right frontal region. Smear and crush cytology was performed using an intraoperative rapid diagnosis specimen. Cytologically, sheet-like tumor cell clusters with round to oval nuclei with nuclear size variation and abundant cytoplasm were noted against a vasculature-rich background. Large cells with irregular nuclear shape, multinucleate cells, tumor cells with nuclear pseudoinclusions, and tumor cells with a foamy cytoplasm were observed. Intercellular lumen-like spaces were also found that were composed of tumor cells with cytoplasmic projections within the tumor cell clusters.
Conclusion : Although the tumor cells of microcytic meningioma showed muclear-size variation and irregular-shaped pleomorphic nuclei, low N/C-ratio and absence of necrosis and mitotic figures are findings that can differentiate it from malignant brain tumors. Intercellular lumen-like spaces are easily visible on cytology specimens but not on frozen histological sections, therefore intraoperative cytology is a very reliable tool for presumptive diagnosis of this particular subtype of meningioma.
