Ovarian clear cell adenofibromatous tumor of borderline malignancy associated with high levels of carbohydrate antigen 19-9.

This report presents a case of ovarian clear cell adenofibromatous tumor of borderline malignancy, which is a rare variant of an ovarian epithelial tumor associated with high levels of carbohydrate antigen 19-9 (CA19-9). A 79-year-old female with a large pelvic tumor underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy; her pre-operative serum CA19-9 level was 780 IU/mL. The diameter of the elastic hard ovarian tumor was 17 cm. Microscopically, many tubular glands lay in an abundant fibrocollagenous stroma. Most of the glands were lined with flattened cells or cuboidal clear cells with large nuclei, but in a small area there were small crowded glands. The epithelium of the glands, in which stratification occurred over three layers, had clear cytoplasmic regions and enlarged nuclei with prominent nucleoli. CA19-9 was immunohistochemically positive in the epithelial cells. The final diagnosis was ovarian clear cell adenofibromatous tumor of borderline malignancy, stage Ia. Postoperatively, her serum CA19-9 level decreased to the normal limit.