Irregular masses seen on two-view mammography are defined as masses with margins that are neither round nor oval. They may demonstrate indistinct, microlobulated, obscured, or spiculated margins and have a variety of densities, ranging from high to low or fat density. Irregular masses tend to imply a more suspicious finding. Multiple irregular masses may be seen unilaterally or bilaterally, and are usually further evaluated with either ultrasound or magnetic resonance imaging and correlated with clinical information. The etiology of multiple irregular masses is vast. This chapter, appearing in the section on asymmetry, mass, and distortion, reviews the key imaging and clinical features, imaging protocols and pitfalls, differential diagnoses, and management recommendations for multiple irregular masses. Topics discussed include metastases, granulomatous mastitis, diabetic mastopathy, and second synchronous cancers.
What is the most appropriate period to define synchronous cancers?