California Cancer Reporting System Standards Volume I: Abstracting and Coding Procedures
Malignant transformation occurs when a benign or borderline tumor transforms into a malignancy.
Create a new case abstract when a benign or borderline tumor transforms into a malignancy (refer to current MP/H rules).
Refer to the most current Multiple Primary and Histology Coding Rules for coding instructions. This applies to cases diagnosed January 1, 2007 and forward.
Do NOT create a second abstract and do NOT change the original histology code when a benign tumor transforms to a borderline tumor.