The patient underwent an exploratory surgery with peritoneal biopsies that revealed a metastatic undifferentiated ovarian carcinoma with immunostaining of epithelial membrane antigen (EMA) and cytokeratin 7 (CK7), and negative immuno-reactivity of WTT, CK 20, PAX8 and hormonal receptors (estrogen and progesterone receptors). The gene discussed is MUC1; the disease is undifferentiated ovarian carcinoma.