Breast biopsy techniques

FNA

Technique
- 21-23-gauge needle, 10mL syringe, USS
- Clean skin, fix the lump between thumb and forefinger, and put the needle tip into the lesion
- Generate negative pressure and move the tip back and forth within the lesion
- Remove the needle
- Make a smear of aspirate on the glass slide and spray it with a fixative
Does not differentiate non-invasive lesions from invasive, if malignant cells are identified
Can have a role in proving multi-focal malignancy, if the first lesion is already known
Also useful for evaluating lymph nodes positive on examination or imaging (sensitivity 90%, specificity nearly 100%). May need to place a clip at time of biopsy.
Needs to contain breast epithelial cells to be diagnostic in most cases

Preferred method for sampling breast lesions
- Allows examination of tissue architecture (differentiation between DCIS and carcinoma)
- Allows immunohistochemistry
Perform under USS, stereotactic, or MRI guidance (use the easiest method available for that lesion)
- USS is best for mass lesions and generally easiest
- Stereotactic is best for calcifications and densities seen on mammogram, but is very uncomfortable (see below)
Technique
- Infiltrate LA to skin, but no deeper
- Make a small nick with a number 11 blade
- Fix the lump between thumb and forefinger
- Penetrate the lump with core needle biopsy (8-14 gauge)
- Warn about clicking sound and fire
- Obtain at least 3 samples from each lesion, and transfer the samples to formalin bottles (if it's a good specimen, it will usually settle within the formalin)
- Clip should be placed and specimens should be imaged to confirm that the targeted lesion has been adequately sampled
Failed biopsy is an indication for localisation and surgical excision

Indications
- Paget's disease
- Inflammatory breast cancer
Technique
- Clean and apply LA
- Use a 4mm punch, use scissors to separate from fat
- Send in formalin
- Pressure/steristrip/suture

Indications:
- Imaging findings and pathologic findings do not correlate
- Atypical ductal hyperplasia
- Atypical lobular hyperplasia
- Radical scar, complex sclerosing lesion
- Papillary lesions
- Cellular fibroepithelial lesions and Phyllodes tumours
- LCIS
- Mucocoele-like lesions
Technique
- Localisation - can discuss with radiologist
  - Hookwire
  - Radioactive seed localisation
  - Intra-operative USS
  - Fluoroscopy (to find the clip)
- Excision
  - Plan the incision as for WLE
  - Raise a skin flap between incision and wire, then grasp the wire with artery forceps
  - Follow the wire using diathermy
  - When you get to the last 2cm of the wire, excise the lesion, marking it with sutures and send it for x-ray
  - Haemostasis
  - Check x-ray +/- re-excise margins
  - Close in layers
Follow-up after excision biopsy
- Patients with benign findings should have a new baseline mammogram 4-6 months post biopsy

False negative rate of 11.8-28.6%
Risk of bleeding, haematoma or infection is less than 1%
Indications
- BI-RADS 4 + 5 require biopsy, BI-RADS 3 is at clinician/patient discretion (according to Kat mostly recommend follow-up with yearly mammogram)
- New suspicious microcalcifications, developing asymmetries, or architectural distortions
- Nonpalpable asymmetry, focal asymmetry, or solid mass on mammogram not seen on USS
- Mammographic lesions corresponding to suspicious areas of enhancement on MRI
Contraindications
- Patient unable to lie prone or co-operate
- Weight
- Lesion location near nipple, too superficial to skin, or too posterior to chest wall
- Lesion mammographically occult
- Patient has severe kyphosis or movement disorders
- Lack of breast tissue thickness for adequate compression
- Pregnancy
Pathologic correlation
- Need concordance with prior imaging reports
- X-ray specimens to see whether recorded calcifications were gathered - if not, quality of biopsy is suspect
Target of biopsy
- Aim for five flecks of calcification, or flecks in three separate cores