A 29-year-old woman comes to the physician for follow-up of a right breast lump. The patient first noticed the lump 4 months ago. It was aspirated at that time, and cytology was negative, but the cyst recurred about 1 month later. The cyst was re-aspirated 2 months ago and, again, the cytology was negative. The lump has recurred. Examination reveals a mass at 10 o'clock, approximately 4 cm from the areola. Ultrasound demonstrates a cystic lesion. Which of the following is the most appropriate next step in management?

Breast lumps are a common complaint in women. Many of these masses are benign processes. Benign conditions of the breast include fibrocystic disease, fibroadenomas, galactoceles, abscesses, and necrosis. It is appropriate to aspirate a palpable macrocyst in the breast; the fluid should be placed on a slide and sent for cytologic evaluation. If the cytology is negative, no fuher treatment is needed. However, when a lesion recurs twice, as has occurred in this patient, open biopsy is warranted. To wait to perform mammography in 1 year (choice A) or ultrasound in 1 year (choice B) would be incorrect management. First, if a malignancy is present, waiting another year will allow progression of the cancer. Second, the mammogram is not definitive. Imaging can contribute information to the workup of a breast mass, but the definitive diagnosis rests on histologic evaluation. Tamoxifen therapy (choice C) is used to both prevent and treat breast cancer. However, this patient does not yet have a diagnosis. She has a cystic mass that has been aspirated twice and has recurred twice. She therefore requires a biopsy to establish a diagnosis prior to the institution of any treatment.