A 63-year-old postmenopausal woman presented to our clinic for annual breast screening. The patient had no family history of breast cancer, or interventional procedure or an operation related to the breast. She had a history of two live births, smoked 20 packs/year, and had no oral contraceptives or hormone replacement therapy. The patient was using levothyroxine only because of hypothyroidism. The patient had no complaints, and the physical examination findings were normal. All mammographic examinations, since 2011, were performed by a digital full-field mammography system (Selenia Dimensions®, Hologic Inc).
The breast structure of the patient was in type B pattern. A 3 mm in size nodular opacity with smooth borders was observed in the upper part of the right mediolateral oblique (MLO) radiograph for the first time in 2016 (Fig. 1a). For the following three years, this density was accepted as an intramammary lymph node (IMLN) due to its localization by different radiology residents because of the lack of an expert breast radiologist (Fig. 1b, c). When examined retrospectively, it is noteworthy that this density grows each year in the two-dimensional plane, albeit quite slowly. However, when 2018 was accepted as the breaking point, it was observed that the density of the lesion slightly increased, and the edges of the lesion were no longer smooth but partially obscured (Fig. 1c). When the patient, who did not participate in the screening program because of the COVID-19 pandemic, finally applied in late 2020, it was noted that the lesion became completely hyperdense in addition to enlargement (Fig. 1d). When looked carefully, the lesion borders were indistinct in all sections.
A hypoechoic mass lesion was observed in the right breast at the 10 o'clock position on ultrasound (US) examination by a linear transducer (Aplio 500, Toshiba Medical Systems Corporation, Canon Inc, Japan) (Fig. 2a). The borders of the vertically located lesion were irregular and indistinct. The echogenicity of the adjacent parenchyma was slightly increased secondary to desmoplastic reaction. No significant vascularization was observed in the lesion on color Doppler images (Fig. 2b). High elasticity values were obtained simultaneously (Fig. 2c). The lesion evaluated in BI-RADS 5 category was sampled by US-guided core biopsy. The histopathological examination revealed as an invasive ductal carcinoma with nuclear grade 2, positive for estrogen receptor (ER) (100%), positive for progesterone receptor (PR) (10%) and negative for human epidermal growth factor receptor 2 (HER2). The Ki-67 labeling index was 16%.
The experienced breast radiologist measured in consensus the largest tumor diameter on each mammogram using a calibrated built-in software tool (Syngo Mammoreport; Siemens, Erlangen, Germany). Caution was exercised to measure reproducibly, consistently and always in the same projection between the serial mammograms. The choice of the projection was based on where the tumor was most clearly discerned. While the lesion continued to grow quite insidiously over the years in the two-dimensional plane, we calculated how much the lesion enlarged in three dimensions retrospectively (Fig. 3).
The patient was operated on the breast-conserving surgery procedure. No lymphovascular or perineural invasion was detected. Sentinel lymph node biopsy was negative. No peri-postoperative complications developed. The treatment process was completed with chemo- and radiotherapy.