Crush Cytology of 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 (). Intraoperatively, 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.\nIntraoperative crush preparations stained with hematoxylineosin showed paucicellular smears composed of a few noncohesive spindle-to-ovoid cells, fragmented collagenous materials, and rare cohesive whorls of round to polygonal eosinophilic cells with a background of bluish mucin (). Scattered polygonal-to-spindle cells contained abundant vacuolated, clear bubbly cytoplasm (, left). Rare intracytoplasmic microcysts were observed (, 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 (). Some scattered polygonal cells had vacuolated cytoplasm within a collagenous material (). In that portion, the tumor cells had eosinophilic cytoplasm with a well-defined border and a refractile, thick hyaline nature, rather than a lacy or fibrillary one (). There were collagen nodules and calcific materials (). No nuclear pseudoinclusions were found. Neither mitosis nor necrosis was found.\nThe near totally removed mass was composed of a microcystic area and a markedly sclerotic area occupying approximately 80% of the mass. Scattered stellate, vacuolated cells and foam cells were observed within the intercellular microcystic area (). Pleomorphic cells with enlarged hyperchromatic nuclei were occasionally found in both sclerosing and microcystic areas. The fibrotic area was composed of fibrous nodules and collagen bundles as well as markedly hyalinized vessels with focal foci of round-to-oval shaped cells in the fibrotic nodule (). In the fibrotic collagenous portion, some spindle shaped tumor cells were found in collagenous nodules and thick hyalinized vessels (). Psammoma bodies were frequently noted. Neither mitosis nor necrosis was found. These findings were reminiscent of microcystic meningioma. Both the spindle cells in the fibrotic area and the meningothelial cells in the cellular portion of typical microcystic meningioma demonstrated positivity for vimentin (prediluted, V9, Dako, Glostrup, Denmark) and negativity for glial fibrillary acidic protein (prediluted, polyclonal, Dako) and S-100 protein (prediluted, polyclonal, Dako). Only meningothelial cells showed focal cytoplasmic reactivity for epithelial membrane antigen (prediluted, E29, Dako). Masson-Trichrome staining highlighted the thick fibrotic collagenous changes of the mass. The edematous fluid in the microcysts was not stained with periodic-acid Schiff or mucicarmine, and was weakly positive for Alcian blue and toluidine blue. The tumor was diagnosed as a microcystic meningioma with extensive sclerosis, World Health Organization grade 1.\nAfter the operation, the patient demonstrated good recovery.