Immunohistochemical and immunoelectron microscopic study of an amylase-producing, CA19-9 positive ovarian mucinous cystadenocarcinoma

Abstract A 75-year-old woman with a right ovarian tumor revealed high levels of serum amylase and CA19-9 which decreased to within normal limits after the operation. A histopathological study of surgically excised tumor tissue revealed a mucinous cystadenocarcinoma. The tumor was composed of three elements: adenoma, adenoma with low potential malignancy, and adenocarcinoma. Using the light microscopic indirect immunoperoxidase technique for amylase and CEA, and the Avidin-Biotin affinity technique for CA19-9 and CA12-5, the amylase and CA19-9 were stained in the cytoplasm of the adenoma and adenocarcinoma although CEA was stained only in the cytoplasm of the adenocarcinoma. An ultrastructural study using the immunoperoxidase method revealed that CA19-9 was positive in the apical portion of the tumor cells and amylase was positive in the entire secretory vesicles of the tumor cells. Furthermore, ciliated tumor cells derived from fallopian tube epithelium were not observed in the light and electron microscopic specimens.