Crush Cytology of Microcystic Meningioma with Extensive Sclerosis

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Microcystic meningioma is an unusual type of meningioma that has been described under various names including humid, myxomatous, vacuolated, or arachnoid trabecular cell meningi-oma. 1 Histologically, microcystic meningiomas are characterized by numerous cystic spaces filled with edematous fluid and intermixed meningothelial cells of stellate or spider shape. Cy-tological descriptions of microcystic meningioma have been limited. 2,3 We recently experienced a case of microcystic meningioma with extensive sclerosis. Intraoperative crush cytologic diagnosis was difficult to establish for the following reasons. First, in microcystic meningiomas, extensive sclerosis is extremely rare. Second, crush cytologic findings of microcystic meningiomas with extensive sclerosis differ from those of conventional me-ningiomas. Here, we emphasize the importance of cytologic diagnosis of this uncommonly encountered microcystic meningioma with extensive sclerosis. A 63-year-old female patient presented with a three-month history of dysarthria and motor weakness of the right arm. Enhanced brain T2-weighted magnetic resonance (MR) images showed a mass measuring approximately 5.4 cm in the left frontal convexity with strong enhancement (Fig. 1). Intraopera-tively, the subdural mass showed marked adhesion to the underlying brain parenchyma and dura, and the lesion had a large feeding artery and high vascularity. Near total removal was performed. Intraoperative crush preparations stained with hematoxylin-eosin showed paucicellular smears composed of a few noncohe-sive spindle-to-ovoid cells, fragmented collagenous materials, and rare cohesive whorls of round to polygonal eosinophilic cells with a background of bluish mucin (Fig. 2A). Scattered polygonal-to-spindle cells contained abundant vacuolated, clear bubbly cytoplasm (Fig. 2B, left). Rare intracytoplasmic micro-cysts were observed (Fig. 2B, right). Nuclear hyperchromasia was frequently found. There were a few clusters of tumor cells having indistinct cell borders and lacy eosinophilic cytoplasm, consistent with whorl-like structures (Fig. 2C). Some scattered polygonal cells had vacuolated cytoplasm within a collagenous material (Fig. 2D). In that portion, the tumor cells had eosino-philic cytoplasm with a well-defined border and a refractile, thick hyaline nature, rather than a lacy or fibrillary one (Fig. 2E). There were collagen nodules and calcific materials (Fig. 2F). No nuclear pseudoinclusions were found. Neither mitosis nor necrosis was found. The near totally removed mass was composed of a microcystic area and a markedly sclerotic area occupying approximately 80% of the mass. Scattered stellate, vacuolated …