Archived Case 49

This mass is microlobulated inferiorly, and much of the margin is indistinct (poorly defined) and obscured (by overlying breast tissue). To be “circumscribed”, a mass must be well-defined (and not obscured) for at least 75% of its margin, and must lack more suspicious findings such as microlobulation and indistinct or spiculated margins.

This mass has suspicious margins on spot mags and is solid and heterogeneous on ultrasound. It lacks an echogenic pseudocapsule, which is a sign of a fibroadenoma or other benign tumor according to Stavros (Radiology 1995). There is significant internal blood flow. These findings are suspicious, although it is possible that this is a fibroadenoma in this young woman.

Before performing core biopsy, one should always document images of the mass about to be biopsied, generally with at least two orthogonal views. This establishes images in your institution (often images done in the diagnostic work-up are performed at another location). It also documents that the mass being biopsied is indeed the mass recommended for biopsy. It also documents the appearance pre-biopsy, since it may change post-biopsy.

It is critical to obtain an image showing the needle in the mass. This documents that you have sampled the mass. I generally obtain a pre- and post-fire shot for each core sample. I obtain 3 good core samples so the pathologist has enough tissue to analyze.

It is not critical to obtain post-biopsy images, unless the appearance of the mass changes significantly OR a clip is placed and mammographic confirmation is desired OR there is a question as to whether or not the ultrasound mass is the same as the mammographic mass, this can be confirmed after the biopsy if the clip is placed.