[A case of primary carcinoid tumor of the testis].

A case of a primary carcinoid tumor of the testis which occurred in a 57-year-old man is reported. The patient was treated by orchiectomy, and no clinical features of a carcinoid syndrome had been noted. The tumor measured 4.0 X 3.2 X 2.0 cm in size and was yellowish in color. Histochemically, the tumor cells were composed in part of argentaffin and in part of argyrophil. Immunohistochemically, the argentaffin tumor cells were positive for neuron-specific-enolase. No tumor cells were positive, however, for neurofilaments, vimentin, keratin, desmin, GFAP, S-100 protein, ACTH, and somatostatin. Electronmicroscopy revealed numerous neurosecretory granules. Tumorous tissue presented a histomorphology of a pure carcinoid tumor composed of parts of argentaffin and argyrophil.