Ultrasound-guided biopsy
Taking cells or a tissue sample from an organ or tumour in the abdomen through the skin, guided by ultrasound imaging — under sedation, without opening the abdomen. It often makes it possible to reach a diagnosis and plan treatment.
What it involves
An ultrasound-guided biopsy involves passing a thin needle through the skin precisely into the spot we see on the screen — into a mass, an enlarged lymph node, or an altered liver, spleen, kidney or prostate. We watch the needle in real time, so we avoid vessels and neighbouring organs.
We distinguish between fine-needle biopsy (fine-needle aspiration, FNA), which collects cells for cytological examination, and core-needle biopsy (Tru-Cut), which collects a small cylinder of tissue for histopathology. We often assess cytology in our own laboratory on the same day; we send histopathology to an external laboratory, and the result arrives in 7–14 days.
This is an examination that changes decisions: it makes it possible to tell an inflammatory change from a tumour, lymphoma from other tumours, to assess whether surgery makes sense and what kind, and to plan chemotherapy without opening the abdomen just to take a sample.
When it is used
We recommend a biopsy when on ultrasound or at examination we see a mass, an enlarged organ or lymph node, and the nature of the change determines what to do next. This applies particularly to tumours of the liver and spleen, abnormal kidney structure, enlarged lymph nodes, changes in the prostate and thickened intestinal walls.
Not every lesion is suitable for biopsy through the skin: highly vascular tumours, suspected haemangiosarcoma of the spleen, or cysts with a risk of spreading require a different approach — in that case we say frankly that surgery is the better choice.
Indications: symptoms that should prompt a visit
- A dog's ultrasound has revealed a mass in the liver or spleen and we need to know whether to operate.
- A cat has enlarged lymph nodes in the abdomen and thickened intestines — lymphoma is suspected.
- An older dog has an enlarged, painful prostate despite treatment.
- Blood tests point to liver or kidney disease, and ultrasound shows an altered structure of the organ.
- Fluid is accumulating in the abdomen for an unclear reason.
- A mass in the abdomen is inoperable, but a diagnosis would make it possible to begin oncological treatment.
Conditions for which we use it in particular
Diagnostics beforehand
Before the biopsy we perform a full abdominal ultrasound (a map of the changes, assessment of the vessels), a blood count with platelet count and a clotting test — puncturing the liver or spleen in a patient with a clotting disorder is dangerous. Biochemistry tells us about the state of the kidneys and liver, and for tumours we also take a chest X-ray in three views, to know whether there are metastases.
The procedure requires sedation or brief anaesthesia, so pre-anaesthetic assessment under STD-01 applies. If the animal is receiving medicines that affect blood clotting (for example some anti-inflammatory drugs), we discuss stopping them a few days beforehand.
How it proceeds
The patient arrives fasted. After the examination, blood results and sedation with a painkiller, we shave and disinfect the skin of the abdomen, and we monitor heart rate, oxygen saturation and blood pressure. The veterinarian locates the lesion on ultrasound, chooses a safe needle path and collects the sample under image guidance: for FNA, several punctures with a thin needle; for a core needle biopsy, 2–3 samples after local anaesthesia of the skin. The procedure takes 15–30 minutes.
After sampling, we watch the puncture site on ultrasound for several minutes to rule out bleeding, and we repeat a check-up scan before discharge. We stain and assess the cytology preparations in our laboratory; if a cytologist’s consultation or additional tests are needed (immunocytochemistry, PCR for clonality), we send them on. The patient goes home the same day after waking up.
Aftercare
Watch the animal for 24 hours: drowsiness after sedation is normal, but pale gums, weakness, an enlarging abdomen or rapid breathing require an immediate phone call. The puncture site needs no care. Limit vigorous activity for 2–3 days.
We usually discuss the cytology result within 1–3 days and the histopathology result after 7–14 days — by phone or at a visit, where we agree the plan straight away: surgery, chemotherapy, conservative treatment or observation with a follow-up ultrasound.
Frequently asked questions
Can a biopsy spread the tumour?
With needle biopsy the risk is very small and mainly concerns certain tumours (for example of the bladder, or some cysts). If this risk is significant for your animal, we will tell you and suggest a different approach.
Is a cytology result always enough?
Not always. Cytology shows cells but not how they are arranged in the tissue; for some tumours and for diseases of the liver or kidneys, histopathology is needed, from a core needle biopsy or after surgery.
Does it hurt?
We perform the procedure under sedation with a painkiller and local anaesthesia of the skin. After waking up, most patients show no discomfort.
Why do we need to test blood clotting?
The liver and spleen have a rich blood supply. In a patient with a clotting disorder, a puncture can cause bleeding that cannot be stopped without surgery — which is why we check this beforehand.
We manage every case individually. The scope, indications and course described above are indicative; we agree the exact diagnostic and treatment plan during the consultation. This content is for information only and does not replace a veterinary consultation.
Do you have questions about ultrasound-guided biopsy?
Call us or book a consultation. We will set out the diagnostic and treatment plan in writing, before you decide.