Optical and electron microscopical study of cytoplasmic granules in human carotid body, carotid body tumours and glomus jugulare tumours

Methods known to selectively stain endocrine cell granules, as well as electron microscopy, were applied to specimens of 7 carotid bodies, 9 carotid body tumours and 6 glomus jugulare tumours. In both normal and tumour glomus cells secretory-like granules were found which displayed staining and ultrastructural features of endocrine or neuroendocrine granules. In most carotid body cells and several tumours round metachromatic granules probably storing polypeptide or protein substances were observed; few carotid body cells and some tumours showed irregularly shaped granules storing 5-hydroxytryptamine. Many tumour cells were filled with lipofuscin bodies, which reacted to some of the granule staining methods giving misleading patterns; they were easily identified by ultrastructural and appropiate cytochemical investigations. Results have been discussed in respect to (1) the probable existence of two types of granular endocrine-like cells, (2) the possible secretion by these cells of substances controlling chemoreception activity, and (3) the close similarity of normal cells with tumoural cells as well as that of carotid tumours with jugular tumours.