**2. Mammography (MMG)**

While MMG is considered the standard initial imaging examination and may reveal microcalcifications and other signs of malignancy, it rarely provides information about the etiology of ND (Rissanen et al., 2007 citing Cabioglu et al., 2003; Dillon et al., 2006; Funovics et al., 2003; Sardanelli et al., 1997; Tabar et al., 1983). In the study by Tabar et al. (1983), only half of the patients who presented with ND and were diagnosed with breast cancer had an abnormal mammogram. In the study by Morrogh et al. (2010), the sensitivity of MMG among all patients with pathological ND was 18%. Conversely, MMG had a high negative predictive value (NPV) and specificity (94%), suggesting that MMG can be used to select patients with physiological ND for whom clinical observation alone may be a reasonable management approach.
