Ultrastructural and electrophysiological features of meningioma whorls in tissue culture.

Cultured cells derived from a psammomatous meningioma were induced to from whorls in vitro by deprivation of nutrients. The ultrastructural features of desmosomes and junctional complexes were similar to sections from the surgical specimen; also prominent were 9-10 nm cytoplasmic filaments. Microelectrode recording of whorled cells showed a larger resting membrane potential than that of similar isolated meningioma cells in culture. Whorl formation seen in this tumor may be a result of relative nutritional deprivation and the need for metabolic cooperation among tumor cells.