The purpose of breast percutaneous biopsy is getting an accurate diagnosis and reducing the number of surgical biopsies.
All infraclinical breast lesions (intangible), visible through ultrasound, can be biopsied using ultrasound as a method of guidance. Percutaneous sampling ensures a reliable cytological or histologic diagnosis through a less invasive gesture, faster and less traumatic than surgical biopsy. In case of histological biopsy, the tissue has a smaller volume, the invasive gesture is not constrained by the additional changes on the mammography. In addition, percutaneous biopsy can be repeated as often as necessary.
In case of infraclinical lesions, the diagnosis strategy depends on the clinical context (risk factors, pathological personal history and family history, patient age), tumor features, evolution and possibility of surveillance of the injury in time. Choosing between cytological, histological biopsy or post-locating surgical excision is depending on the imaging characteristics of the lesion, availability of equipment and physician experience. Interventional maneuvers are performed only after achieving complete imaging standard (possibly additional mammographic screenings, MRI or CT) because the post-biopsy aspect may change through the appearance of a possible hematoma.
The patient is informed about the biopsy method proposed (risks, limitations, side effects and alternatives). From anamnesis data is recorded about the patient medication, any history related clotting disorders and / or allergic reactions. Treatment with anticoagulants shall be postponed 7-10 days prior to the percutaneous biopsy. Evaluation of hemostasis parameters (prothrombin time, bleeding time etc.) is indicated only for patients undergoing anticoagulant treatment or in case of prolonged bleeding risk. In cases where treatment can not be interrupted, it can perform a cytological biopsy or an 18 G needle micro-biopsy.
Fine needle aspiration biopsy (cytological biopsy)
Is a routine technique in the management of breast masses.
Advantages of cytological biopsy consist in being able to inject or aspirate fluid or air, the simplicity of the technique and in obtaining cytological result extremely fast (even on the spot if the cytologist is present). Also the cytological biopsy is well tolerated by patients.
Executing the procedure under ultrasound guidance allows biopsy of infraclinical injuries. The technique can even be used for lesions located near the chest wall or breast implants.
The most commonly used needles are those of 21 to 23 G with a length of 3.8 to 4 cm. Longer needles are needed for deep localized lesions and / or large breasts. Thinner needles are flexible and can deflect during sampling in addition their view is somewhat more difficult.
The syringes used are 10-20 ml with or without intermediate flexible tube. Local anesthesia is generally not used for cytological biopsies.
To monitor the sampling procedure through ultrasound, the doctor uses a hand to manipulate the transducer, while with the other hand, making the biopsy.
Both cysts and other fluid collections are easily aspirated with a percutaneous needle biopsy. Sometimes cysts with viscous content can be difficult to differentiate from solid lesions. In these cases, eco guided percutaneous aspiration can avoid the need for surgical biopsies or a clinical reassessment.
Cytological examination of the aspirated fluid is indicated in the cases where the liquid has a bloody or viscous appearance.
Bacteriological examination of aspirated fluid is indicated in case of suspected breast abscess and infected cyst.The performances of cytological biopsies are variable, depending on the number of passages made, the character of the lesion and of course the operators and cytologists experience.
Thick needle biopsy permits sampling tissue fragments useful for histopathological exam. Percutaneous eco-guided micro biopsy is used increasingly as an alternative to excisional biopsy (surgical) in the evaluation of breast masses. The method avoids surgery diagnoses in 76-85 % of infraclinical (intangible) injuries. The diagnostic value of percutaneous micro biopsy, when performed by a trained medical team, is comparable to a surgical biopsy.
The equipment required for percutaneous breast micro biopsy
There are many types of percutaneous tissue sampling tools. Out of these, the most used in breast pathology are the automated ones, in which they insert 14-16 caliber G needles. Those are generally 10 cm in length and have a long ‘trip’ (22-23 mm).
There are two different types of automatic pistols. The classic one, which works with Tru -Cut type needles; allows taking a tissue fragment with half-cylinder aspect. The other type of pistol works by suction / cutting mechanism, obtaining cylindrical tissue fragments. With this latest model with a needle of the same caliber the extracted tissue fragment has an almost doubled volume. In particular, this is the type used for breast lesions because it can obtain a high quality tissue fragment using 18 G needle ( thinner than 14 G ) which allows easier penetration through the skin and mammary parenchyma.
Breast microbiopsy technique
After planning the insertion point in the skin lesion, the skin is sterilized the breast is covered with a sterile field. Local anesthesia is performed using 3-7 ml of 1% lidocaine, injection under ultrasound. Before needle insertion, the mechanism is tested and the noise is presented to the patient so that she is not surprised or scared by it during the procedure.
At the end of the procedure, during 10-15 minutes, manual compression is applied over the biopsied area with or without an ice pack. Then a compression bandage is applied and the patient is instructed to avoid aspirin for three days and physical exercise for 24 hours.
Complications of breast biopsies
Side effects are generally minimal: bruising, pain (which can be calmed by administration of acetaminophen or ibuprofen) and vasovagal reactions. Complications are exceptional for cytological biopsy and micro-biopsy. These include: prolonged bleeding, bruising and infection.An extremely rare complication in case of breast micro-biopsy is iatrogenic pneumothorax that can occur due to failure to parallel approach the chest wall.The sensitivity of the eco-guided microbiopsy in breast cancer diagnosis varies depending on the type of lesion, needles, number of tissue fragments collected and medical experience.