benign to malignant?

I noticed a lump one year back,did FNAC,result shows benign ductal gland.A year passed & am now diagnosed with cancer.Is there any possibility of a benign cells turning into a malignant cells?

[Cleveland Clinic]

Dear mazami:  The question in this situation is whether the cells in the FNA were representative of the lump.  In other words, did the biopsy include enough cells to get a representative sample of the lump.  The other question is whether this is the same lump or whether there is something about it that changed or is it a different lump.  A malignant cell is a cell that has mutated or changed over time in such a way that it no longer has the properties of a benign cell.