Question: The pathology report for our patient being investigated for ovarian cancer mentions “Serous tumor of low malignant potential (atypical proliferative serous tumor of ovary).” Can we report code C56.- for this diagnosis? Florida Subscriber Answer: Low malignant potential tumors are also known as borderline tumors according to the American Cancer Society (Source: www.cancer.org/cancer/ovarian-cancer/treating/low-malignant-potential.html), and as such, cannot be reported as malignant with a code from: Instead, you should think of it as a tumor of uncertain behavior, and you should use one of the following, as applicable and determined upon pathology and provider notation: