Metastatic Ovarian Carcinoma Showing Histological Features Similar to Primary Ovarian Carcinoma:—A Case Reprot with Histological and Immunohistological Analyses—

Differential diagnosis of ovarian neoplastic lesions is occasionally difficult even when histological examination is performed. We report the case of a 67-year-old woman with a lower abdominal mass, in which primary ovarian cancer was clinically difficult to distinguish from metastaic ovarian cancer. She had a history of mastectomy of both breasts. Comparison of microscopic specimens suggested that the ovarian lesion had metastasized from the breast cancer. However, immunohistochemical staining revealed that the ovarian lesion was positive for AE 1/3 (cytokeratin), EMA (epithelial membrane antigen), ER (estrogen receptor) and PR (progesterone receptor) . It was also focally positive for CK7, NSE (neuron- specific enolase) and CGA (chromogranin A) . While these results were not sufficient to clearly distinguish whether this tumor was derived from breast or ovary, the neuroendocrine nature (focal positivity for NSE and CGA) suggested that it was more likely to be derived from the breast. Careful microscopic examination of many specimens is necessary in cases of ovarian neoplastic lesions. Immunohistochemical staining can be helpful for differential diagnosis but is not necessarily conclusive.