Argyrophil cells in Brenner tumors: histochemical and immunohistochemical analysis.

Argyrophil cells were identified by the single-impregnation Grimelius technique in 11 of 28 (39%) Brenner tumors, accounting for less than 1% of the tumor cell population in all the cases. All tumors with argyrophil cells were stained to demonstrate calcitonin, somatostatin, gastrin, adrenocorticotropic hormone, neurotensin, insulin, glucagon, and serotonin; and four of them (three benign and one borderline) were also stained for chromogranins with the monoclonal antibody LK2H10. Serotonin was present in nine of the 11 cases with argyrophil cells. Neurotensin and somatostatin were found in one borderline tumor, which also contained serotonin. Chromogranin reactivity was demonstrated in all four cases in which it was examined. Ultrastructural examination of one tumor revealed that the argyrophil cells contained secretory granules, 80 nm in diameter, and had elongated cytoplasmic processes that extended between the more numerous nonargyrophil tumor cells. The argyrophil cells of Brenner tumors are similar to those of urothelium in the frequency with which they are immunoreactive for serotonin and the rarity with which they are reactive for peptide hormones. These cells differ from those of mucinous ovarian tumors, which often contain both serotonin and peptide hormones. The findings of this study lend additional support to the close similarity of the epithelial components of Brenner tumors and urothelium.