Hemidesmosome-like intercellular specializations in human meningiomas.

Desmosomes, gap junctions and tight junctions are intercellular specializations which have been described in human meningiomas. We report, in five of five meningiomas, including a pulmonary metastasis from a malignant intracranial meningioma, a fourth type of intercellular specialization which is similar to but not identical with the hemidesmosome of the epidermis. Idential intercellular specializations have been described between arachnoidal cells, but not between dural fibroblasts. The presence of the junction in human meningeal neoplasms of diverse histologic pattern supports the origin of the meningioma from arachnoidal epithelium. The consistent occurrence of these structures in a pulmonary metastasis as well as benign intracranial tumors suggests that they may be a useful morphologic marker in the differential diagnosis of putative extracranial metastatic meningiomas.