Ovary, Low-grade serous carcinoma

Low-grade serous carcinomas (LGSC) are uncommon ovarian malignancies. They are defined as any invasive serous carcinoma with low grade nuclear features and low mitotic activity (usually less than 12 mitoses/10 HPF). LGSCs usually arise from serous borderline tumor (often micropapillary type), and, like serous borderline tumors, have a high frequency of KRAS and BRAF mutations but a low frequency of p53 mutations. Other patterns of LGSC include: 1) micropapillary serous carcinomas (characterised by long filliform non-branching papillae without stromal cores); or 2) psammocarcinomas (with massive psammomatous calcifications). While the majority of LGSCs present at stage II or higher at the time of the diagnosis, the overall survival time has been reported as 81.8 months, significantly longer than high grade serous carcinoma of similar stage.