Multiple Circumscribed Masses
A circumscribed mass is a mass with margins demonstrating a sharp demarcation between the lesion and surrounding tissue. On mammography, at least 75% of the margin must be well defined in order for the mass to qualify as circumscribed. Multiple circumscribed masses may be seen unilaterally or bilaterally and can be seen on up to 1.7% of screening mammograms. After mammography, these masses may need to be further evaluated with ultrasound and correlated with clinical information. 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 circumscribed masses. Topics discussed include cysts, fibroadenomas, oil cysts, metastases, lymph nodes, and neurofibromas.