A New Mass Three Years After Lumpectomy Was Fat Necrosis

What happened, in summary

A 55-year-old woman had a 1.1 cm mass detected at the 12 o’clock position of the left breast. Biopsy showed grade 2 invasive ductal carcinoma that was ER-positive, PR-positive, and HER2-negative.

She underwent lumpectomy with placement of a BioZorb marker. Because the superior surgical margin was positive, a re-excision was performed. Sentinel-node biopsy was negative, and postoperative radiation followed.

Three years after lumpectomy, surveillance mammography showed a new low-density mass forming in front of the BioZorb site. Ultrasound demonstrated several areas that appeared to represent evolving fat necrosis. Because the finding was new and located near the treated tumor bed, stereotactic biopsy was performed to exclude recurrence.

Pathology confirmed fat necrosis and was considered consistent with the imaging appearance. The new mass therefore represented a benign treatment-related change rather than a return of the breast cancer. Her case shows why new densities around a BioZorb marker may still require tissue sampling even when imaging suggests a benign process.