[Investigations on the ultrastructural cytology of branchiomeric paragangliomas (author's transl)].
The paragangliomas of the jugular and carotid bodies are growth processes which show varying histological and cytological patterns. The real nature of these lesions is still a matter of discussion. In this study 6 jugular and 3 carotid body tumours were investigated using the electron microscope. The main components were irregular cells with short and long cytoplasmic processes closely packed and mostly arranged in complexes. The ultrastructural cytology of the jugular and carotid bodies showed no striking differences. The great majority of the cells exhibits a clear similarity to the cells of normal paraganglia, especially to chief cells of carotid bodies (type I cells). But there were some modifications in the cellular structure including the abnormal structure of mitochondria and a greater variation in the morphology of the dense cored granules. The cytoplasm was dominated by differing populations of mitochondria comprising such of the crista type and such showing tubulus-like structures with a dense matrix and very often intramitochondrial bodies. The characteristic feature was the occurrence of randomly distributed dense cored granules measuring 700-800 A in diameter. These granules display a homogeneous electron dense or moderately dense somewhat granular core which is separated from limiting membrane by a clear electron lucent halo. A further population of granules was of a greater dimension (3,000-4,000 A) revealing an oval or cigar-like shape. In contrast to the former type the homogeneous dense cores of these granules showed a smooth contour and the lucent halo was very narrow. In general, singular exocytotic phenomena could be supposed. More frequently, however, signs of granulolysis were encountered. Free ribosomes, arranged often as polysomes, sparse, disorderly distributed microfilaments of 60-80 A diameter, few 240 A-microtubules and some lysosomal structures are also observed. Usually the cell clusters abutted directly upon the vascular connective tissue. In other cases cytoplasmic processes are intercalated resembling sustentacular cells. Fenestrated capillaries known to be typical for the paraganglionic tissues were only seldom detected. In the interstitial tissue typical collagen fibres are found showing a periodicity of 600-700 A, but occasionally fibres with a periodicity of about 1,200 A could be seen resembling fibrous-long-spacing collagen. Synaptic junctions and nerves or axons were always lacking.