A 28 year old woman presents with a painless lump in her left breast. This was first discovered 5 years ago and diagnosed to be a fibroadenoma. Subsequently, she opted for observation alone.

However, the lump rapidly increased in size over the past 1 year, prompting her to seek medical attention. No other symptoms were present.

Her medical history is otherwise unremarkable and she is not on any medications, including oral contraceptives. There is no family history of breast, ovarian, or gastrointestinal malignancies.

She has two children, both of whom were breastfed, for a total of 2 years. Her menarche was at 12 years of age, and her menstrual cycles are regular. She does not smoke, and only drinks socially.