Non Small Cell Carcinoma Metastasis to Meningioma
A 71-year-old woman was admitted to our institution with a 3-week history of left arm weakness. She had undergone a right upper lobectomy for carcinoma of the lung 2 years ago ().\nA computed tomography imaging of the brain revealed a right frontal cerebral convexity mass lesion surrounded by peritumoral edema, which presented with marked contrast enhancement. Brain magnetic resonance imaging (MRI) showed a few hypointense areas surrounded by a diffuse hyper-intense lesion in T2 weighted images; contrast-enhanced T1 weighted MRI showed "a dural tail sign" attached to homogeneously enhancing mass ().\nThe patient refused surgery because deemed her symptoms to be not serious. Ten months following this initial discovery, she came to the hospital with left hemiparesis. MRI showed increased size of the mass ().\nCerebral angiography showed that the hypervascular mass was supplied by bilateral middle meningeal arteries. In addition, an incidental unruptured aneurysm at the anterior communicating artery was found (). The clipping of anterior communicating aneurysm was perfomed first through the left pterional approach. After a month, a right frontal rectangular craniotomy crossing midline was performed for tumor removal. The tumor presented as an encapsulated mass firmly attached to the dura, a typical characteristic of a meningioma. The central part of the tumor was firm, and the peripheral part was friable. The mass was completely removed. The post-surgical course was uneventful.\nMicroscopic examination revealed fibrous meningioma, and irregularly bran-ching gland-like adenocarcinoma cell clusters intermixed with this fibrous meningioma in some areas (). The metastatic cancer cell clusters were enclosed by a rim of benign histologically distinct meningioma tissue. Histologic features of this adnocarcinoma were identical to those of the patient's pulmonary adenocarcinoma resected 2 years ago. Immunohistochemical (IHC) staining for TTF-1 and CK7 were positive in this adenocarcinoma, and IHC staining for EMA and vimentin were positive in the background fibrous meningioma. These findings were compatible with a metastasis of pulmonary adenocarcinoma into the meningioma, so-called "tumor-to-tumor metastasis". Post-operative chemotherapy was administered.