Testicular Biopsy
Testicular biopsy removes a small piece of testis for histology, and in infertility it is also used to retrieve sperm. It is done for two main reasons: to find out why a man has no sperm in the ejaculate (azoospermia) and whether sperm can be retrieved for assisted reproduction, and to diagnose or exclude testicular cancer and its precursor lesion, in selected patients.
In infertility, an open biopsy through a small scrotal incision removes tissue from one or both testes. For sperm retrieval, testicular sperm extraction (TESE) takes several samples, and microdissection TESE (micro-TESE) uses an operating microscope to find tubules that are larger and more likely to hold sperm.
Fine needle aspiration and percutaneous needle biopsy are less invasive options in obstructive disease. Tissue is placed in a special fixative (Bouin or modified Davidson solution), because formalin distorts testicular architecture.
The procedure takes 20 to 60 minutes under local, spinal or general anaesthesia. In men with obstructive azoospermia, sperm are retrieved in over 95%. In non-obstructive azoospermia, sperm retrieval rates are about 40 to 60% with micro-TESE, depending on the cause: about 20 to 30% in Klinefelter syndrome with highly variable results, higher in hypospermatogenesis and lower with Sertoli cell only pattern or microdeletions of certain regions of the Y chromosome.
Indications.
- Azoospermia with a normal sized or small testis, to separate obstructive from non-obstructive causes when the clinical, hormonal and imaging findings are unclear.
- Retrieval of sperm for intracytoplasmic sperm injection in obstructive and non-obstructive azoospermia, and after failed vasectomy reversal.
- Severe oligozoospermia or failure of fertilisation, in selected cases.
- Suspected testicular intraepithelial neoplasia (germ cell neoplasia in situ) in high risk men: contralateral testis in patients with testicular cancer, undescended testis, atrophic testes or infertility with microlithiasis.
- Unexplained testicular mass when an inguinal approach is not appropriate, and diagnosis of rare infiltrative conditions.
- Before gonadotoxic treatment (cancer therapy) when sperm preservation is needed and no ejaculated sperm can be obtained.
- Research and assessment of testicular function in selected syndromes.
Not indicated in men with a clearly obstructive cause that can be repaired directly, or when the diagnosis is already clear from hormone levels and clinical findings and sperm retrieval is not planned.
Contraindications and precautions.
- Local infection of the scrotum, skin, or epididymis.
- Uncorrected bleeding disorder, anticoagulant treatment.
- Suspected testicular tumour in the case of a mass: the approach is by inguinal route and not through the scrotum, to avoid spread of tumour cells.
- Unfit for anaesthesia.
- A fertility team plan, with the partner's assessment and a laboratory ready to cryopreserve the sperm, before the retrieval is done.
- Genetic testing before the procedure (karyotype, Y-chromosome microdeletions, and cystic fibrosis gene testing in obstructive azoospermia), and counselling about the implications for children.
Preparation and technique.
The patient has semen analysis (at least two samples, with centrifugation to look for sperm), hormones (follicle stimulating hormone, luteinising hormone, testosterone), scrotal ultrasound, and genetic tests. Consent includes the chance that no sperm is found, the risks, and the effect on testosterone.
Under anaesthesia, the scrotum is opened over the testis, the tunica is incised, and testis tissue is removed. In micro-TESE, the surgeon uses a microscope to select tubules. Tissue is placed in the right medium for sperm retrieval (to the laboratory immediately) or fixative for histology, the tunica and skin are closed, and an ice pack and scrotal support are used.
