Endometrial Sampling

The endometrium is sampled when pathology is suspected; this may be when the patient experiences a change in her normal pattern of menstrual bleeding or when bleeding is unexpected e.g. after the menopause.
When a patient presents with any of these symptoms the GP should undertake a full pelvic examination, including speculum examination of the cervix.
Guidelines are available on when to refer urgently.¹

• Nulliparity
• Family history of endometrial or colonic cancer
• Tamoxifen or unopposed oestrogens
• Polycystic ovary syndrome
• Obesity

• Transvaginal ultrasound measurement of endometrial thickness has become a routine procedure and an initial investigation in patients with abnormal uterine bleeding.
• There is debate as to whether a cut-off of 5 or 4 mm endometrial thickness should be employed. 5 mm has become standard for the postmenopausal patient.³
• If the endometrial thickness is above these values, polyps have been diagnosed or the patient is presenting with recurrent bleeding, endometrial disease has to be excluded by histological assessment.
• Outpatient aspiration curettage has superseded dilatation and curettage, which was previously considered to be the gold standard for obtaining endometrial tissue and provides the same sensitivity in detecting endometrial disease.⁴
• Hysteroscopy allows visualisation of the uterine cavity and the opportunity for targeted biopsy and removal of endometrial polyps.

• Performed without prior cervical dilatation.⁵
• Introduced in the 1930s using narrow metal cannula with side opening with serrated edges and syringe attached for suction as instrument removed.
• As the cannula is rotated during removal, a strip of endometrium is peeled off and sucked into the syringe.
• Causes significant cramping during removal.
• More recent alternative is the Vavra curette requiring vacuum source and also causing significant cramping.
• Recent research has trialled transcervical instillation of 5 mls 2% lidocaine. This significantly reduced pain during endometrial sampling.⁶

Today the most popular device is the disposable Cornier's pipelle.⁷

See related article on the procedure involved in Pipelle Endometrial Sampling.

• Bimanual examination to asses the uterus.
• The cervix is then visualised and cleaned.
• A tenaculum is applied to the anterior lip of the cervix, and is used to provide gentle traction whilst a sound is inserted though the cervical os. This minimises the risk of perforation.
• Dilators may be required if there is difficulty in passing the sound.
• When the position and size of the uterine cavity have been assessed, the pipelle is inserted through the cervical os and advanced until gentle resistance is felt.
• The inner piston of the device is then withdrawn to create suction and the endometrial sample is obtained by moving the pipelle up and down within the uterine cavity by approximately 2-3cm but not beyond the cervical os.
  
  
• This procedure should be repeated at least four times and the device rotated 360 degrees to ensure adequate coverage of the area.
• The pipelle is then withdrawn from the cervical os and the endometrial sample expelled into a solution of formalin for transport to the laboratory.

Pipelle endometrial sampling can also be combined with hysteroscopy.
Other devices include Gravlee 'jet washer', Mi-Mark spiral sampler, Gynoscann surface stripper (based on IUCD insertion principle), the H Pipelle⁸ and the Tao brush.⁹

These include:

• Prolonged bleeding
• Infection
• Uterine perforation and post procedure pain
• Bacteraemia can occur after endometrial sampling (antibiotic prophylaxis must be given to patients at risk of endocarditis¹⁰)

Has been traditional technique for obtaining samples of endometrium for pathological examination.
However ' blind ' D and C has been shown to miss significant amounts of pathology including:

• Endometrial polyps
• Intrauterine mucous fibroids
• Small areas of endometritis
• Hyperplasia or cancer
• Lost IUDs

• Uterine perforation. This is rarely serious with healing usually rapid and complete.
• It is more common in post-menopausal or post-partum women.
• False passage in cervix or cervical damage producing cervical incompetence from large dilator.
• Infrequently postoperative infection or intrauterine adhesions.

Hysteroscopy is gold standard but not always readily available.

• 3-5mm deep biopsy obtained with hysteroresectoscope loop.
• This is used to identify adenomyosis or investigate deep lesions of the endometrium.
• Permanently removes a narrow strip of basal endometrium with underlying myometrium.
• Usually heals well.