Introduction 1 2 3 4 5 6 7 8 9 10 11 12 13 14 12 13 14 15 16 17 17 18 19 Materials and methods 9 Mammograms were obtained in the mediolateral oblique and craniocaudal direction on a digital mammographic unit (Senograph 2000 D or a Senograph DS, GE Healthcare, Wis., USA). Detection, density of the lesion compared with breast tissue, lesion morphology, and size were scored. In the morphologic assessment, lesion type was classified as either a mass, a calcifications or as an architectural distortion. Lesion shape was described as rounded, lobulated or irregular and lesion margins as sharp, vague or spiculated. The size of the tumor was measured by determining the longest axis through the displayed lesion. Spiculae surrounding a solid lesion were interpreted as desmoplastic reaction and not included in the measurement. MRI investigations were performed on a 1.5-Tesla system with a double breast coil (Magnetom Vision, Sonata or Symphony, Siemens, Erlangen, Germany). In the scanning, we used a coronally orientated three-dimensional fast low-angle shot (FLASH 3D) with the following parameters: TE 4 ms, TR 8.1 ms, FA 20°, FOV 360 mm, TA 96 s, image resolution 1.5 mm × 1.5 mm × 1.5 mm for all patients scanned prior to June 2004 and TE 4 ms, TR 7.5 ms, FA 8°, FOV 320 mm, TA 87 s, image resolution 1.3 mm × 1.3 mm × 1.3 mm for all patients scanned after June 2004. Prior to the MR examination, an intravenous catheter was inserted. All patients were placed in the prone position, with the breasts in the double breast coil and positioned at the isocenter of the magnet. After localizer images were obtained in three directions and a precontrast FLASH 3D series was recorded, 0.1 mmol/kg bodyweight gadolinium chelate (Magnevist, Schering, Germany or Dotarem, Guerbet, The Netherlands) was administered using a power injector (Spectris, Medrad, USA) at 2.5 ml/s followed by a 15-ml saline flush at the same injection rate. Thereafter, five post contrast FLASH 3D series were recorded. 19 20 All studies were evaluated retrospectively by two radiologists in conference and consensus. BRCA-MCs and controls were mixed during the evaluation. Except from the knowledge of a malignancy being present, the radiologists were blinded to any other clinical information. Mammography and MRI images were evaluated in separate sessions. From the histopathology reports, the tumor type, size and mitotic activity index (MAI) were recorded. The study was approved by the institutional review board; since the study was performed retrospectively, informed consent was not required according to the review board. t P Results Six BRCA-MC cases could not be matched according to the criteria defined; these cases were excluded from the study. Four BRCA-MCs were excluded because no match could be found based on patient’s age; the other two were excluded because no match could be found based on tumor size. The mean age and tumor size of the excluded cases were, respectively, 33 years (range 27–36, median 35, SD 3.4 years) and 1.4 cm (range 0.6–2.8 cm, median 1.1 cm, SD 0.8 cm). A total of 29 BRCA-MC cases were included for this study. In the BRCA-MC group, five women were symptomatic (17%); 21 women were symptomatic in the control group (83%). P 0.289 P 0.371 The mean tumor size on mammography was 2.1 cm (range 0.5–7.0 cm, median 1.5 cm, SD 1.49 cm). The mean tumor size on MRI was 2.4 cm (range 0.6–7.1 cm, median 1.8 cm, SD 1.75 cm). P P P P P 1 P P P Table 1 Mammographic lesion characteristics for both groups   BRCA-MC group Control group P Lesions detected  n n  Lesion type Mass 19 13 0.042 Arch. distortion 1 4 0.345 Calcification 2 5 0.216 a Hyperdense 8 1 0.050 Isodense 11 12 0.050 a Rounded 12 3 0.036 Lobulated 1 – 1.000 Irregular 6 10 0.029 a Sharp 9 1 0.024 Vague 8 8 0.473 Spiculated 2 4 0.194 a P P P 2 P P P P P P P Table 2 MRI lesion characteristics for both groups   BRCA-MC group Control group P Lesions detected  n n  Lesion morphology Rounded 16 7 0.010 Lobulated 3 3 1.000 Irregular 8 18 0.010 Lesion margins Sharp 20 7 <0.001 Vague 6 15 0.017 Spiculated 1 6 0.049 Enhancement pattern Homogeneous 8 5 0.304 Heterogeneous 12 22 0.009 Rim 7 1 0.025 Enhancement kinetics Type 1 1 2 1.000 Type 2 4 6 0.525 Type 3 22 20 0.380 Discussion 13 BRCA1 BRCA2 12 21 22 12 13 23 8 9 24 24 9 25 26 27 1 28 12 13 29 29 30 31 9 Fig. 1 a BRCA1 b arrow arrow  19 2 Fig. 2 a BRCA1 arrow b  17 32 We conclude that in BRCA-MC malignant lesions frequently have morphological characteristics that are commonly seen in benign lesions, like a rounded morphology or a sharp delineation. This applies for both mammography and MRI. However, the possibility of MRI to evaluate the enhancement pattern and enhancement kinetics of lesions enables the radiologist to detect characteristics suggestive for a malignancy.