Mammography, sonography and MRI for detection and characterization of invasive lobular carcinoma of the breast.

Imaging of invasive lobular carcinoma (ILC) is more challenging than other types of breast cancer because of its spider web like growth pattern. Mammography has a relevant number of false negative exams, especially in dense breasts. Mammographic appearance of ILC is often subtle. Distinct mass like aspects are absent more often when compared with other types of breast cancer, and lesions are frequently only mildly opaque. Microcalcifications are uncommon. The addition of an ultrasound exam can improve rates of detection and diagnosis of ILC, but even when combining modalities ILC can be missed. If clinical signs are suspicious, magnetic resonance imaging (MRI) can help to detect ILC. MRI should also be considered in preoperative staging if treatment with breast conservation is favoured, particularly to assess maximal tumor dimensions. Mammographic findings do not correlate well with pathological tumor size. Additional tumor sites detected by MRI only should be validated cautiously, and guidelines established for multicentricity detected by mammography should not be used in the same way.