Most ovarian mucinous carcinomas are organ-confined (Stage I) at the time of presentation and have excellent prognosis. Those associated with infiltrative stromal invasion do worse than broad-based expansile invasion consisting of back-to-back glands. Patients with extra-ovarian disease at the time of diagnosis usually succumb to their tumors. Recurrences do not respond well to chemotherapy or radiation. The presence of anaplastic carcinomatous mural nodules in organ-confined (Stage I) tumors does not appear to worsen the prognosis. The 5-yr survival rates are as follows: 83% (Stage I), 55% (Stage II), 21% (Stage III), and 9% (Stage IV). The image shows mucinous carcinoma with destructive stromal invasion. The invasive foci are composed of distorted glands, isolated tumor cells, and small nests or clusters of cells with high-grade nuclear features that are haphazardly infiltrating desmoplastic stroma.