Two distinct case reports with foamy cell and differential diagnosis: Xanthomatous meningioma and review of literature

Meningiomas are the most common primary intracranial tumor thought to derived from arachnoidal cap cells in the meningeal coverings of the spinal cord and brain. The current WHO classification, published in 2016, includes nine different subtypes of grade 1 meningiomas, three different subtypes of grade 2 meningiomas, and three different subtypes of grade 3 meningiomas. Metaplastic meningioma is a rare variant which shows focal or diffuse mesenchymal tissue component. Xanthomatous meningioma which has foamy cell changes is a quite rare variant of metaplastic meningioma. Two patients, 54 and 59 years old, who applied to our clinic with similar symptoms, were operated for meningioma. Histopathological examination of their biopsy showed that neoplastic cells had oval-round nuclei and eosinophilic cytoplasm. In xanthomatous meningioma, some neoplastic cells had clear vacuolated cytoplasm (foamy cells). In microscopic examination of resection material in one of these patients, cells in some areas of the tumor had clear vacuolated cytoplasm (foamy cells). These neoplastic cells were scattered among other meningothelial cells and they were positive for EMA. To the best of our knowledge, until today there have been only 14 reported xanthomatous meningioma cases in English literature. Here, we aimed to discuss the pathogenesis and differential diagnosis of xanthomatous meningioma in two different cases.