need more data to evaluate your question like type of mass is it tender or nontender . what family history ?? i mean first generation or???

Any way try to explain hope it will be of help
if the mass is palapable you first step in managment and treatment is needle aspiration if it is clear and disapper then do followup in 4 to 6 weeks to see if the fluid if the aspiration material is not clear i mean bloddy send to cytology examination to rule out the possibility of itracyctic carcinoma.
if the mass persist after the aspiration then your next step is excision.
you can even do ultrasound to distinguish btwn the solid and cyst type of mass
she have family history for breast cancer so you have to screen her!!!