A dense mass in a mammogram only means that there is something that is different from the rest of the breast tissue. Your health care provider will advise if further testing is needed to determine the nature of this finding.
"Dense breasts" on a mammogram is a normal finding. A "thickness" on mammogram is not a typically used phrase; ask your health care provider to clarify what the results actually say.
It simply means that dense areas are breast lumps that need to be evaluated by its size and if its malignant.
Mammogram not elsewhere classified
An ultrasound is ordered if the radiologist sees a suspicious area on your mammogram. Often this is dense tissue, but, still, you should follow up rather than taking the order casually.
A diagnostic mammogram is an imaging study (X-ray) that is used to visualize the breast. It is used either as a screening test or to rule mass lesions. Oftentimes, it is ordered in conjunction with an ultrasound. The ultrasound is another imaging study to differentiate the nature of the mass. For instance, if the mammogram showed a mass in the right upper quadrant of the left breast then it should be followed by an ultrasound to differentiate a solid mass from a simple cyst.
When an area of tissue on a mammogram is "isoattenuating," it means that it is of the same density as a reference tissue, and thus attenuates x-rays equally. When no reference tissue is explicitly stated, the surrounding tissue is usually implied to be the reference tissue. For example, to say, "the mammogram showed that the breast mass in question is isoattenuating," means that breast mass is the same density as the normal surrounding breast tissue.
it is stable
mass: the amount of matter in a substance (your welcome)
Atomic Mass Unit
In some contexts, it may mean mammogram or mammography.
BI-RADS 4 on a mammogram means there is a suspicious abnormality, and a biopsy might be required. It does not necessarily mean cancer.
Not necessarily. The weight of an object is determined by its mass and the force of gravity acting on it, while density is a measure of how much mass is packed into a given volume. An object can be heavy without being dense if it has a large volume.