Intrasellar Clear Cell Meningioma Mimicking Invasive Pituitary Adenoma: A Case Report and Review of the Literature İnvaziv Hipofiz Adenomunu Taklit Eden İntrasellar Berrak Hücreli Menenjiyoma: Olgu Sunumu ve Literatürün Gözden Geçirilmesi

The authors report on a 55-year-old man with complaints of intermittent pulsatile headache for 6 months, vision loss of the right eye and diplopia for 2 months. A magnetic resonance image (MRI) showed a large heterogeneously enhanced intrasellar mass lesion, occupying the entire hypophyseal fossa and extending into the sphenoid sinus. The patient underwent microscopic transsphenoidal surgery for removal of the tumor. Microscopic examination with hematoxylin&eosin and immunohistochemical staining of the tumor specimen was performed and confirmed the diagnosis of clear cell meningioma (CCM). Though postoperative MRI indicated gross total resection of the tumor, rapid recurrence was detected at 4 months after surgery. Gamma knife radiotherapy was administered. To the authors’ knowledge, the present case is the first case of transsphenoidal removal of CCM. We reviewed the current literature on this rare histological type of meningioma in the sellar region. KeywOrds: Clear cell meningioma, Pituitary adenoma, Differential diagnosis