Pulmonary meningioma. Immunohistochemical and ultrastructural features.

Two cases of solitary primary pulmonary tumors showing the immunohistochemical and ultrastructural features of meningothelial meningiomas are presented. The benign clinical and radiologic course, the negative computed tomography scan of the brain (case 1), and negative neuropathologic investigation (case 2) support the diagnosis of a primary pulmonary meningioma rather than a metastazing malignant intracranial meningioma. Negative neuroendocrine markers (neuron-specific enolase, chromogranin, bombesin) and the lack of neurosecretory granules by electron microscopy confirm the diagnosis of this rare pulmonary tumor.