Metastatic meningioma in fine-needle aspiration (FNA) of the lung: cytomorphologic finding.

Pulmonary metastasis of intracranial meningioma is rare. We present the cytomorphologic features of such a tumor in a 71 yr-old woman who was found to have multiple lung nodules 13 years following the resection of an atypical intracranial meningioma. Cytomorphologic features were quite distinct and included hypercellularity with large syncytial groups of monomorphic cells with epithelioid morphologic features, often in perivascular arrangements. Occasional intranuclear cytoplasmic inclusions as well as binucleated cells with wispy cytoplasmic extensions were also noted. Immunoperoxidase studies showed focal positivity for epithelial membrane antigen. The differential diagnosis includes primary or metastatic adenocarcinoma, malignant mesothelioma, and melanoma.