Not all palpable masses will appear on an ultrasound or mammogram. Each test has it's limitations and what it can pick up. For example, an ultrasound is better at differentiating between a mass that is solid or fluid filled. A solid mass on ultrasound may not show up. On mammogram certain characteristics can show up such as microcalcifications, or a density, but it too has its limitations.If you are too concerned about this lump,ask your doctor,who has the all the details about your case, to consider if a biopsy would be necessary to find out the nature of this lump.Best wishes .
thanks, i am planning to call my doc next week.