[Malignant meningioma with adenocarcinoma-like metaplasia: a rare entity to be not misdiagnosed]. / Le méningiome malin avec métaplasie adénocarcinomateuse: une entité rare à ne pas méconnaître.

ABSTRACT

We report on a 51-year-old woman who presented with a cervical spinal cord tumor clinically suspected to be a metastasis. Histological examination revealed an anaplastic meningioma containing epithelial nests arranged in a gland-like pattern suggestive of adenocarcinoma. This component strongly expressed cytokeratins whereas the meningothelial component was vimentin--epithelial membrane antigen--and progesterone receptor-immunoreactive, suggesting either anaplastic meningioma with adenocarcinoma-like metaplasia, or adenocarcinoma metastasis in a meningioma, but the search for a primitive neoplasia including thoracic-abdominal-pelvic computed tomography and mammography was negative. Anaplastic meningiomas with adenocarcinoma-like metaplasia are uncommon lesions, 4 cases having been reported in the literature so far. Their immunohistochemical and chromosomal characteristics are similar to those observed in secretory meningiomas. When available, fluorescence in situ hybridization detects the same chromosomal alterations in the two components, confirming a common clonal origin. This observation demonstrates the necessity to perform the correct diagnosis of malignant meningioma with adenocarcinomatous metaplasia, whose prognosis and treatment radically differ from those of metastatic adenocarcinoma located in a meningioma.