This case is noteworthy for several reasons:

1. Cancers in patients this young are very scarce. You are not going to see many. Most lesions like this will invariably turn out to be fibroadenomas on biopsy. This should not deter you from biopsy of lesions that do not meet criteria for benign. You are obliged to biopsy these lesions when you see them.
2. There is an obligation to track BIRADS III and IV and see they are not lost to follow up.
3. Lesions that are not clearly benign justify biopsy.
4. It's unusual for carcinoma in someone this young to grow so slowly over a period of almost 3 years. Generally, cancers in patients this young tend to grow aggressively and metastasize early.
5. Real-time review is essential in breast ultrasound. Do not interpret these cases from static images. Either put your hand on it or put your foot in it.