Ultrastructure of malignant paraganglioma of organ of Zuckerkandl.

Electron microscopic study of a malignant paraganglioma of the organ of Zuckerkandl revealed similarities between the tumor and the normal paraganglia. The well-differentiated portion of the tumor recapitulated the structure of the basic functional units of the paraganglion. In addition there signs of anaplasia both at the histologic and ultrastructural level. Large neurosecretory granules were noted in some of the tumor cells, but most of the cells were agranular. Crystaloids resembling those seen in alveolar soft part sarcoma were also noted. The study supports the theory on the common origin and histogenesis of paragangliomas and alveolar soft part sarcomas.