Meningioma microcístico com metástase pulmonar em canino: relato de caso / Microcystic meningioma with pulmonary metastasis in canine: case report

Meningiomas são os principais tumores primários do sistema nervoso central (SNC) que afetam cães e gatos. Na maioria dos casos, são neoplasias benignas, geralmente expansivas, causando compressão do SNC, e raramente fazem metástase para outros órgãos. O presente trabalho tem como objetivo relatar a ocorrência de um meningioma microcístico com metástase pulmonar em um canino de 11 anos de idade, com sinais clínicos de andar cambaleante, compressão da cabeça contra objetos, agitação, salivação e agressividade. Na necropsia, foram observadas, no encéfalo, massas bem delimitadas pardo-avermelhadas, firmes, de aspecto granular, localizadas no córtex parietal e nos núcleos da base. Inúmeras micronodulações de aspecto semelhante foram observadas no pulmão. Histologicamente observaram-se nódulos formados por células neoplásicas fusiformes, com núcleos grandes e alongados e nucléolos evidentes, dispostas de forma frouxa, formando vacúolos e microcistos. À imuno-histoquímica, o meningioma apresentou marcação fortemente positiva para citoqueratina e negativa para vimentina. Por meio da histopatologia e da imuno-histoquímica, foi possível estabelecer a classificação histológica de meningioma microcístico, bem como diferenciá-lo de outras doenças que cursam com sinais nervosos.(AU)

Meningiomas are the main tumors of the central nervous system (CNS) affecting dogs and cats. In most of the cases they are benign neoplasms, usually expansive, causing compression of the CNS and rarely metastasize to other organs. We describe the occurrence of a microcystic meningioma with pulmonary metastasis in an 11 - year - old canine with clinical signs of staggering gait, head compression against objects, agitation, salivation and aggressiveness. At necropsy, well-defined, firm, granular-looking masses located in the parietal cortex and nuclei of the base were observed in the encephalon. Numerous micronodulations of similar appearance were observed in the lung. Histologically, nodules formed by spindle neoplastic cells with large, elongated nuclei and evident nuclei were loosely arranged, forming vacuoles and microcysts. Immunohistochemistry were strongly positive for cytokeratin and negative for vimentin. Through the histopathology and immunohistochemistry, it was possible to establish the histological classification of microcystic meningioma, as well as to differentiate from other diseases that present with nervous signals.(AU)

Microcystic Meningioma - Unusual Variant of Meningiomas

Microcystic meningioma is a rare variant of meningiomas. This unusual variant was originally described by Masson, who labeled it "humid". The computed tomographic scan or magnetic resonance images of these tumors resemble those of a glial or metastatic tumor with cystic or necrotic changes. There is no definitive method for differentiating cystic meningiomas from these more common tumors. But immunohistochemically, they share a similar pattern of positive staining for epithelial membrane antigen and vimentin with other meningiomas. Our case was a 34-year-old woman with a tumor mass on the right frontal area. She was admitted to hospital because of generalized tonic seizure. Grossly all of the tumor could be removed, and histopathologically this tumor was revealed to be a microcystic meningioma.

On the clinicopathology, ultrastructure and immunohistochemistry study of intracranial microcystic meningioma / 中国癌症杂志

Purpose: To enhance one's ability to diagnose intracranial microcystic meningioma. Methods: Fifteen cases of intracranial microcystic meningioma have been studied either clinicopathologically, or ultrastructurally or immunohistochemically. Results: The results indicate that electron microscopy and immunohistochemically are very helpful for the diagnosis of the tumor. There was no predilection as to location, however the tumor was more common on the base of skull. Vacuole-like structure and/or vesicular dilatation could be seen in the cytoplasm and capillaries could be observed in between the spindle cells by light microscopy. Under electron microscopy, the processes separated from each other and formed into a cystic structure, and bundles of collagenous fiber could be found in it. In immunohistochemistry, the stains with vimentin and epithelium membrane antigen (EMA) were positive. Conclusions: Intracranial microcystic meningioma has some characteristics under the microscope, immunohistochemistry is helpful in its diagnosis, and election microscopy can confirm this diagnosis.

Microcystic Meningioma: Case Report

Microcystic meningioma, a distinct morphological variant of meningiomas, is histologically characterized by a vacuolated appearance with multiple cystic spaces lined by vacuolated or stellate-shaped tumor cells. This unusual variant was originally described by Masson, who labeled it "humid". The clinical and morphological findings point toward a benign course. And these unusual morphological variants of meningioma are potentially curable tumor. But there is no definitive method for preoperatively differentiating microcystic meningioma from the malignant glioma. We report a case of microcystic meningioma occurring in the left frontal area of 74 year old woman, with malignant clinical nature.

Microcystic Meningioma: A case report

Microcystic meningioma, a distinct morphological variant of meningiomas, is histologically characterized by a vacuolated appearance with multiple cystic spaces lined by vacuolated or stellate-shaped tumor cells. We report a case of microcystic meningioma occuring in right frontoparietal area of 42-year-old woman, with emphasis on differential diagnosis, along with a review of literatures. Immunohistochemically, most of the tumor cells demonstrated positive immunoreactivity for both epithelial membrane antigen and vimentin. Electron microscopy showed that the extracellular space was extensive, where eletron-lucent material was occasionally seen. The tumor cells had long cytoplasmic processes showing complex interdigitation and a large number of desmosomes.