Case 12

A. 1:00 (upper outer quadrant)

Explanation: To interpret a mammogram, one must become familiar with the proper way to describe the location of a finding such as a mass or calcifications. Standard reporting should include the following:

• Laterality (left or right breast)
• Quadrant (upper outer, upper inner, lower outer, or lower inner)
• O’clock face (i.e. 12:00, 1:00, 2:00, etc…)

O’clock face is determined by visualizing that you are standing in front of the patient, looking at the breast with a clock superimposed upon it. Note that any o’clock position will not be in the same quadrant of each breast (i.e. a 2:00 mass in the right breast is upper inner quadrant, but a 2:00 mass in the left breast is upper outer quadrant).

As per the ACR BI-RADS manual, other location descriptors that can be used are:

• Depth (anterior third, middle third, or posterior third)
• Distance from the nipple
• A few terms that can be used in lieu of a quadrant: “central”, “retroareolar”, “axillary tail”

Determining the quadrant and o’clock face of a finding requires being familiar with the standard display of a mammogram. If you are not yet familiar with the orientation of a mammogram, see the below annotations:

A. BI-RADS 0 (Incomplete); Recommend diagnostic ultrasound

Explanation: This is the patient’s first (baseline) mammogram and there is a left breast mass in the upper outer quadrant that needs further characterization before deciding final management. Targeted diagnostic ultrasound is the correct next step.

D. BI-RADS 3 (Probably Benign); Six month follow-up

Explanation: This non-palpable, solid, circumscribed oval mass can be assessed as “Probably Benign”, meaning that it has a less than a 2% chance of being malignant. The assessment of BI-RADS 3 can be given with a recommendation for short term follow-up (diagnostic ultrasound in six months). Once two years of stability has been documented for this mass, it can finally be designated benign with no specific follow-up needed.

As per the ACR BI-RADS manual 5th edition, there are three mammographic findings which can be designated as BI-RADS 3, Probably Benign:

1. A solid mass which is non-palpable, non-calcified, circumscribed, oval or round (as seen in this case).
2. A non-palpable focal asymmetry with no ultrasound correlate.
3. A solitary group of punctate calcifications.

C. Lymph Node

Explanation: This is the normal sonographic appearance of an intramammary lymph node, with a thin hypoechoic cortex and a hyperechoic fatty hilum.