Three cases of serous borderline
tumors of the ovary with areas of serous low-grade
carcinoma metastatic to the anterior mediastinum simulating multilocular
thymic cysts are presented. The patients are women between the ages of 33 and 50 years. The 3 women had a prior history of primary
ovarian neoplasms diagnosed over a period ranging from 3 to 20 years; the 3 patients were in stages IIIA, IIIB, and III. Follow-up radiologic examination revealed the presence of an anterior mediastinal
tumor. The 3 patients underwent surgical resection of the mediastinal
tumor. Grossly, the mediastinal
tumors measured from 7 to 9 cm in greatest diameter and were described as cystic with solid areas. Focal areas of
hemorrhage were present, but frank
necrosis was not identified. Histologically, all the
tumors basically showed similar histopathologic features, namely, those described in multilocular
thymic cysts, ie, cystic structures lined by either squamous or low cuboidal epithelium, lymphoid
hyperplasia,
cholesterol cleft
granulomas, and remnants of thymic tissue. In addition, within the cystic structures, there was a neoplastic cellular proliferation with papillary architecture, nuclear atypia, and scattered mitotic figures. Immunohistochemical studies for
keratin, MOC31, and CA-125 showed positive staining in
tumor cells while
placental-like alkaline phosphatase was negative. Two patients remain alive and well after follow-up ranging from 6 to 18 months and 1 patient died of
tumor 18 years after initial diagnosis.