Tissue culture, electron microscopic and enzyme histochemical investigations of extraadrenal paragangliomas.

Light and electromicroscopical as well as histochemical investigations were performed on three cases of extraadrenal paragangliomas. They were localized in the carotid body, tympanicum and cauda equina region. Tissue of two cases was cultivated in vitro in nutrient medium TCM 199. The tumours were classified as paragangliomas of the paraganglionic type with typical cell clusters, of the adenomatous and angiomatous type. The enzyme histochemistry showed a very high dehydrogenase activity. Ultrastructurally numerous typical osmiophilic granules could be observed in the cytoplasm of the tumour cells. In tissue culture only a minimal cellular proliferative activity could be detected. The few proliferating cell colonies showed mostly characteristics of epithelial tissue and sometimes a similar behaviour to cells of a ganglioneuroblastoma. The minimal proliferative activity in vitro is in good agreement with the proliferative behaviour of the extraadrenal paragangliomas in vivo.