Detection of chromogranin in argyrophil cells of endometrial carcinoma

Normal and neoplastic endometrial tissues were examined immunohistochemically for chromogranin which was shown to be a specific marker for neuroendocrine cells. All 20 normal endometriums and 20 endometrial carcinomas without argyrophilia were chromogranin negative. Endometrial carcinomas with argyrophilia tested were composed of three groups; 10 with type I argyrophil cells, 20 with type II argyrophil cells, and 10 with both type I and II argyrophil cells. Type I argyrophil cells of 20 endometrial carcinomas were all chromogranin positive. Chromogranin immunoreactivity was also intimately correlated with the Grimelius reactivity in type II argyrophil cells of 19 endometrial carcinomas, 13 with only type II argyrophil cells and 6 with mixed type of argyrophil cells. Chromogranin was absent in type II argyrophil cells of 11 endometrial carcinomas, 7 with type II argyrophil cells and 4 with mixed type of argyrophil cells. Chromogranin negativity was related to the disappearance of argyrophilia after diastase digestion in 5 of these 11 tumors, and also partly to mucinous substances in the remaining 6 tumors. In conclusion, the results obtained suggest that some of type II argyrophil cells are neuroendocrine in nature as well as type I argyrophil cells.