Was workup at the first visit adequate?
Workup was totally inadequate. The referral of a palpable mass always necessitates workup unless the ultrasound shows a simple lesion like a cyst or fibroadenoma. My personal preference is to see breast ultrasound images in real time when this is the clinical history.
How does a delay in diagnosis of breast carcinoma affect survival?
Delayed diagnosis gives a worse outcome, in general terms.
Generally speaking, how do premenopausal cancers behave biologically compared with postmenopausal breast cancers?
Premenopausal cancers tend to grow faster and they behave biologically more aggressively. There are exceptions as always but this is a general rule of thumb.
Would you do a contralateral mammogram?
Yes. To get a baseline for the contralateral breast.
What breast imaging would you suggest for this patient's sister?
The patient's sister is at higher risk for developing a breast malignancy than the general population. Depending on where you live, she should start with mammograms when she is 28 years old i.e. 5 years before the age at which the patient was diagnosed.
On the first image there are calcifications visible in the ducts extending in a radial fashion from the posterior aspect of the areola. This is a very good image of the ultrasound of DCIS.