This turned out to be an infiltrating ductal carcinoma of the left breast. The FNA of the node was positive for malignant cells.
There are several teaching points in this case:
- This is not ever a fibroadenoma. It is poorly defined and has no pseudocapsule. Red flag. If it does not look like a fibroadenoma it probably isn't one.
- The parenchyma of the lesion is heterogeneous, a very unusual finding for a fibroadenoma. Red flag.
- The echogenicity of the node cortex is unusually high.