here is some information from the Mayo Clinic:
Lumpectomy
Breast Biopsy
Here are the code descriptions from EncoderPro:
19101- Biopsy of breast; open, incisional - The physician removes tissue for biopsy. The physician makes an incision in the skin of the breast near the site of the suspect mass. The mass is identified and a sample of the lesion is removed. This specimen is often examined immediately. If the lesion is benign, the incision is repaired with layered closure. If malignant, the incision may be closed pending a separate, more extensive surgical session, or a more extensive surgery may occur immediately, in which case this code would not be reported
19125 - Excision of breast lesion identified by preoperative placement of radiological marker, open; single lesion - The physician uses radiologic markers to identify breast tissue to be excised for biopsy. The physician makes an incision in the skin of the breast over the site of the lesion marked for excision by preoperative placement of a radiological marker. The lesion and marker are excised. Bleeding vessels are controlled with electrocautery or ligated with sutures. A drain may be inserted into the wound. The incision is sutured in layered closure and a light dressing is applied. Report 19126 for each additional lesion identified by a preoperative marker and removed during the same surgical session
19301 - Mastectomy, partial (eg, lumpectomy, tylectomy, quadrantectomy, segmentectomy); - The physician excises a breast tumor and a margin of normal tissue by performing a partial mastectomy by making an incision through the skin and fascia over a breast malignancy and clamping any lymphatic and blood vessels. The physician excises the mass along with a margin or rim of healthy tissue. This procedure is often referred to as a segmental mastectomy or a quadrantectomy, but is also called a lumpectomy. In 19302, an axillary lymphadenectomy is also performed. The lymph nodes between the pectoralis major and the pectoralis minor muscles and the nodes in the axilla are removed through a separate incision. A drainage tube may be placed through a separate stab incision to enhance drainage from the wound or lymphatic system. The incision is repaired with layered closure and a dressing is applied