Could you please explain, in lay terms, what my pathology report read as "Fat Necrosis, Lymph Node(s) Exhibiting Reactive Follicular Hyperplasia." I'm a 38 yr old, breast reduction two years ago, sister w/DCIS age 40. Found a rubbery mass near armpit, Diagnostic mammo/ultrasound clear, but noted dense breasts, assymetry, which my radiologist said was very common post breast surgery. Surgeon agreed to remove mass, which ended up to be quite large, 3.2 x 2.0. She assured me the findings were very benign, and my surgery/fat necrosis in the breast area are the most likely reason the nodes were enlarged. Does your clinic demand a DEFINITIVE answer as to why nodes in this area are enlarged, or should I be satisfied with "the most likely" answer? Do doctors ever know the definitive reason for node enlargement, or is this the best answer I should expect?