The use of testicular biopsy was first reported in the late 1930s by Professors Hotchkiss and Engle at Cornell Medical Center, New York Hospital, USA. The original purpose of testicular biopsy was to identify obstructive azoospermia and primary varicocele insufficiency. It is mainly indicated in patients with azoospermia who have normal testicular size (>15cc), normal testicular texture, palpable vas deferens and normal serum FSH levels.
The purpose of testicular biopsy is to find out whether the spermatogenic function of the testes is normal. The biopsy allows direct examination of testicular tissue and is the “gold standard” for determining testicular function. Testicular biopsy is a simple surgical procedure that can be performed in an outpatient operating room, and local anesthesia is sufficient. The procedure takes about 5-10 minutes. Depending on the patient’s condition, a unilateral testicular biopsy can be performed, or a bilateral biopsy can be performed.
During the procedure, a small amount of testicular tissue is removed and preserved in a special preserving solution called Bouin’s fluid, and then sent to the pathology department where the tissue is stained and examined by a pathologist under a microscope.
Due to the local anesthesia used during the procedure, the patient does not feel any particular pain. For a few days after the procedure, the patient may experience a mild dull pain, which can be relieved with a small amount of analgesic medication if necessary.
Because testicular biopsy is, after all, a surgical procedure, most doctors use it as the ultimate test and only perform it as a last resort. Before you decide to perform a testicular biopsy on a patient, you should first consider whether the results will change the original treatment plan and whether there is a less invasive alternative to the test.
Testicular biopsy is particularly indicated for patients with azoospermia. Patients with oligospermia do not require a testicular biopsy, and in these patients, the biopsy results are often normal. This is not surprising; after all, the patient has sperm present in the semen, and these sperm are clearly produced in the testes.
In the past, doctors took only a small piece of tissue for pathology during a testicular biopsy. Today, however, we all know that biopsy tissue taken from one site alone does not truly reflect the entire testis. Within the testis, sperm production is not uniformly consistent; some areas will have vigorous sperm production, while others will have poor or even no signs of sperm production. In particular, in patients with non-obstructive azoospermia, spermatogenesis is even more heterogeneous due to testicular insufficiency.
This means that in order to understand the true spermatogenic status of the testis, the doctor needs to take samples from at least 4 different areas of the testis and send them separately for examination.
In the past, testicular biopsy was a purely diagnostic tool. Today, testicular biopsy is also an effective means of obtaining testicular sperm for couples suffering from infertility due to male factors. The sperm obtained through biopsy can be used for intracytoplasmic sperm injection (ICSI). Specialized fertility centers can also cryopreserve testicular biopsy tissue. This frozen testicular sperm is very useful and can be readily used for assisted reproduction, especially in patients with small testicular volumes, and by freezing the testicular tissue, a subsequent testicular biopsy can be avoided for assisted reproduction.
Although testicular biopsy is easy to perform, the accurate reporting of biopsy results is a rather difficult task and requires expertise in this area. When examining the biopsy specimen, the physician needs to look for evidence of sperm production in the varicocele. Some patients have no spermatogenesis at all (absence of spermatogenesis), while others show a stagnation of spermatogenesis at a certain cellular stage and an inability to produce mature sperm (spermatogenic blockage). All these manifestations suggest testicular insufficiency and are usually irreversible, for which there is no effective treatment. In fact, the key point of the examination is to find out whether the patient has partial or total testicular insufficiency, which is the main reason why multi-point testicular biopsy is emphasized. A patient with total testicular insufficiency presents with no signs of sperm production in the entire testicle, while a partial testicular insufficiency presents with a few areas that can still produce sperm normally. Although a few areas of the testis can produce sperm, the number of sperm produced is too small to reach the semen, resulting in a zero sperm count on semen examination.
Conversely, if a patient has perfectly normal testicular sperm production but no sperm in the semen, there is an obstruction present in the reproductive ducts, a condition known as obstructive azoospermia, and for such patients, testicular biopsy is particularly valuable.
Although testicular biopsy is not a complicated procedure, it can have very troublesome consequences if not performed properly. Improper biopsy can result in local adhesions and fibrotic scar formation and make subsequent vasal epididymal reconstruction more difficult, so it is best to have it done by a specialist. Again, the most common problem with testicular biopsies is the inability of the pathologist to accurately report the biopsy results. Accurate interpretation of testicular biopsy results is a difficult task that cannot be performed by a general pathologist and requires a specialized specialist to perform this task well. After the biopsy specimen is examined, it should be properly stored for use in another consultation. If it is not stored properly, once it is needed for a follow-up consultation, it will need to be biopsied again, causing unnecessary pain and expense to the patient.
1, testicular open meatus biopsy: the earliest and still commonly used. The operation is simple, safe, complete, and convenient for pathologists to make a diagnosis. The disadvantages are slightly traumatic, limited sampling area, and inability to completely reflect the spermatogenic function of the whole testis.
2, testicular open microsurgical biopsy: a new method developed in recent years. It is especially suitable for patients with poor spermatogenic function of the testis. During the operation, the white membrane of the testis is incised, the testicular tissue is separated and observed under the microscope, and selective biopsy is performed on the tissue with normal shape and structure, and the sperm detection rate is higher for patients with partial regional insufficiency of the testis.
3, Percutaneous testicular puncture biopsy: Percutaneous testicular puncture biopsy (Percutaneous testis biopsy) requires the use of a specialized puncture gun (Tru-Cut), which needs to be performed under local anesthesia and can be used to evaluate the histological and cytological manifestations of the testis. Due to the large blindness of puncture, it can easily lead to epididymal or testicular artery injury. In addition, the specimens obtained by puncture are small, containing only 3-6 tubular structures per needle of tissue. For patients with obstructive azoospermia, this method can be chosen to obtain testicular sperm for ICSI.
4. Percutaneous testicular fine-needle aspiration biopsy: Fine-needle aspiration biopsy is less risky and less painful. The extracted tissue needs to be evaluated with the help of flow cytometry. This method is often used to obtain testicular sperm for use in ICSI. Open biopsy is still the preferred method of examination for diagnostic purposes.
Open testicular meatus biopsy
Open microsurgical biopsy of the testis
Percutaneous testicular fine-needle aspiration biopsy Percutaneous testicular aspiration biopsy
Percutaneous testicular fine-needle aspiration biopsy