Diagnosis of Extensive DCIS with Progressive Microcalcifications over a Period of 11 Years

A 53-year-old woman presented complaining of enlargement of her right breast; 12 years earlier she was treated elsewhere for an invasive ductal carcinoma of the right breast with breast-conserving surgery, adjuvant chemotherapy, anti-HER2 therapy, radiotherapy and endocrine therapy. One year postoperatively, a group of microcalcifications was seen in the ipsilateral breast on mammography. In the following years, the area of microcalcifications progressively increased, but instead of vacuum-assisted biopsy, the treating physicians performed core needle biopsies that were negative for malignancy. Twelve years after initial diagnosis, when we first examined the patient, the right breast was diffusely hard on palpation and larger than the left. On ultrasound, a large area of architectural distortion was seen in the lower-inner quadrant; after core needle biopsy, histology showed extensive fibrosis with almost complete absence of cells. Due to the progressive enlargement of the area of microcalcifications, simple mastectomy with sentinel lymph node biopsy was performed. Final histology showed extensive areas of high-grade ductal carcinoma in situ (DCIS), pTis, pN0. This case highlights the long period of time that DCIS may exist without progression to invasive disease and possible caveats that may delay diagnosis of DCIS with potentially serious medicolegal implications.