Thank you very much for your reply.
How are you? It's good that you are having regular mammogram and check-ups. Ultrasound has excellent contrast resolution and quickly determines if a suspicious area is in fact a cyst or an increased density of solid tissue. On the other hand, lymph nodes may become enlarged or swollen any time they produce additional white blood cells to ward off an infection. These infections are often benign and may swell from the formation of an abscess in the nodes or if they contain cancer cells.
In patients who has been diagnosed with breast cancer, it is usually wise to be cautious and biopsy any enlarged lymph nodes if the swollen node persists for beyond a month or two since it may contain cancerous cells. If your lymph node is less than one centimeter in diameter and soft, rubbery and tender, it is more likely to have swollen due to a benign cause, such as recently shaving under the arm, using a new deodorant, having a manicure, or injury. Otherwise, it is a reason for worry. Either way patients are advised to return for follow-up observation and evaluation especially that you have an increased risk (2x) because of your mother's diagnosis.
I hope this helps. Take care and keep us posted.