For a woman under 30 with unilateral discharge, what is the recommended initial imaging study?

In the case of a woman under 30 who presents with unilateral discharge, the recommended initial imaging study is an ultrasound, with or without a mammogram. In this age group, breast tissue is typically more dense, which can make mammograms less effective in assessing abnormalities compared to ultrasound.

Ultrasound is particularly useful as a first-line imaging modality in evaluating breast conditions because it can help differentiate between a solid mass and cystic lesions, as well as assess for any potential abnormalities in the underlying breast tissue. Moreover, ultrasound is safe and does not involve exposure to ionizing radiation, making it especially appropriate for younger women.

While a diagnostic mammogram can also be performed, especially if there are concerning findings from the ultrasound, it is not usually the first choice for women under 30 due to the density of breast tissue in this demographic, which can obscure findings. A CT scan of the abdomen is generally irrelevant in the evaluation of breast discharge, as it does not provide pertinent information regarding breast pathology. A biopsy is also not the initial step unless there is a clear indication from imaging that necessitates one to determine the nature of a mass or abnormality. Thus, ultrasound serves as an effective first approach in this scenario.