Dear Sonost, It is difficult to say what this discharge is, nipple discharge can be due to hormone fluctuations. Of concern is if this discharge is spontaneous, from only one-side, sticky like the consistency of an egg white or bloody. An ultrasound is used to try to determine if the lump is fluid filled which would be more indicative of a cyst. A mammogram might be used but in young women, because there is a higher ratio of breast tissue to fat, the breasts are more dense and the information obtained from a mammogram might not be useful. They may opt to try to drain or take a sample from this lump to evaluate the situation further.