Endometrial Biopsy

CHAPTER 143 Endometrial Biopsy



Beth A. Choby


Endometrial biopsy (EMB) is a safe and cost-effective diagnostic method of evaluating the endometrium. EMB is an office-based procedure most commonly used in perimenopausal and postmenopausal women to investigate abnormal uterine bleeding (AUB) and to rule out endometrial cancer. Endometrial cancer is the most common invasive gynecologic malignancy, and endometrial hyperplasia is sometimes a precursor. EMB may be considered in any woman with risk factors for endometrial hyperplasia or cancer (Box 143-1).



Box 143-1 Risk Factors for Endometrial Hyperplasia and Cancer



Age >50 years

Atypical endometrial hyperplasia

Chronic anovulation

Diabetes

Infertility

Menopause after 55 years of age

Nulliparity Chronic anovulation

Obesity*

Tamoxifen

Unopposed estrogen therapy


* 21 to 50 pounds overweight carries relative risk three times less than >50 pounds overweight.


Although EMB is sensitive enough to diagnose hyperplasia or cancer, it is less useful for detecting abnormalities such as endometrial polyps or the changes of endometrial atrophy. The false-negative rate for EMB is 5% to 15%. Although EMB was the preferred initial procedure for evaluating AUB and had mostly replaced dilation and curettage (D&C), it is now more often used in conjunction with other procedures. Hysteroscopy, transvaginal ultrasonography for endometrial thickness, and sonohysteroscopy are often combined with or done in lieu of EMB (see Chapter 140, Hysteroscopy). Because EMB is cost effective, efficient, and readily available in the outpatient setting, it continues to be an important diagnostic tool.



Anatomy


The EMB involves transcervical sampling of the endometrial lining. An endocervical curettage of the cervical canal is performed as part of the EMB.



Indications



• Evaluation of premenopausal and postmenopausal AUB

• Work-up of infertility, especially short luteal phase or anovulation

• Assessment of the effects of hormone therapy

• Investigation of atypical glandular cells or endometrial cells on Papanicolaou (Pap) smear in women older than 40 years of age

• Failure to respond to medical treatment of AUB

• Evaluation of abnormal endometrial thickness on transvaginal ultrasonography

• Surveillance in women previously diagnosed with endometrial hyperplasia

• AUB in women with risk factors for endometrial cancer (see Box 143-1)

• Women with an intact uterus receiving unopposed estrogen therapy

• Evaluation for endometrial carcinoma or precancerous changes

• Identification of causes of dysfunctional uterine bleeding

• Evaluation of uterine enlargement in conjunction with ultrasonography

• Screening in hereditary nonpolyposis colon cancer syndrome (HNPCC). The lifetime risk of endometrial cancer in women with HNPCC ranges between 32% and 60%. Annual or biennial endometrial biopsy or transvaginal ultrasonography is recommended in women with HNPCC beginning at 30 to 35 years of age. Recommendations are based on expert opinion because the effectiveness of gynecologic surveillance is not definitive. Diagnosis of HNPCC requires histologically confirmed colorectal cancer in three relatives, at least one of whom must be a first-degree relative. Two successive generations must be affected and one case has to be diagnosed before 50 years of age. Screening is appropriate in known carriers of this autosomal dominant gene or in cases where there is strong suspicion of HNPCC.


Contraindications



Absolute



• Pregnancy

• Bleeding diathesis/coagulopathy


Relative



• Use of anticoagulant therapy

• Active vaginal, cervical, uterine, or pelvic infection

• Cervical stenosis

• Morbid obesity

• Significant pelvic relaxation with uterine prolapse


Equipment


A variety of instruments are available for EMB. The more popular methods are described for comparison. Equipment common to all methods is listed here; additional items required with specific aspirators are listed in the aspirator descriptions.


• Large Graves vaginal speculum

• Povidone–iodine solution in nonallergic patients

• Cotton balls

• Ring forceps

• Uterine sound

• Single-tooth tenaculum

• Endocervical curette without basket (e.g., Kevorkian curette)

• Buffered formalin specimen containers with patient identification labels (two)*

• Endometrial sampler (special equipment requirements by method)
• Disposable flexible plastic endometrial aspirator (e.g., Pipelle, Pipet Curet, Endocell)

• Scissors

• Reusable stainless steel curette (Novak or Randall)

• 20-mL syringe

• Disposable endometrial aspirators with syringe suction (Cannula Curette, Uterine Explora, Explora II)

• A Tis-U-Trap endometrial curette or a Vabra aspirator (disposable)

• External suction pump

• Brush sampler (Tao Brush)

Cervical dilators should be kept available (see Chapter 136, Cervical Stenosis and Cervical Dilation).




Precautions



• The previous Pap smear should be reviewed before the procedure. If no recent smear report is available and it is indicated, obtain one before proceeding with the endometrial biopsy (EMB).

• A bimanual examination identifies extreme uterine anteversion or retroflexion. There is an increased risk of uterine perforation when sounding the uterus or collecting the EMB if significant angulation is present between the cervical neck and uterus.

• The use of small cervical dilators is often necessary in women found to have cervical stenosis, so they should be available. Methods for managing cervical stenosis are described in Chapter 136, Cervical Stenosis and Cervical Dilation.


Preprocedure Patient Education and Forms



• Obtain a thorough history and review pertinent clinical records (see encounter form online at www.expertconsult.com). Explain to the patient the indications for the procedure, the process itself, side effects, and potential complications so that she may provide informed consent. See the sample patient education handout and the sample patient consent for “Endometrial Biopsy” available online at www.expertconsult.com.

• Nonsteroidal anti-inflammatory drugs (NSAIDs) effectively decrease uterine cramping during EMB. Patients can be instructed to take 600 to 800 mg of ibuprofen orally 30 to 60 minutes before the procedure unless they are allergic to aspirin or NSAIDs. Other NSAIDs have similar efficacy.

• In extremely anxious patients, premedication with an oral anxiolytic such as 10 mg of diazepam (Valium) 1 hour before the EMB is an option. Patients receiving these medications should be counseled to bring a family member to drive them home.

• The American Heart Association does not recommend antibiotic prophylaxis against bacterial endocarditis before EMB because the procedure is unlikely to cause bacteremia. No current studies specifically stratify this risk.

• Postmenopausal women can be scheduled for EMB at any time, although significant bleeding episodes are best avoided to optimize sample size.

• EMB in reproductive-age women is best performed on day 22 or 23 after the first day of the last menstrual period. The presence of secretory glands confirms that ovulation has occurred. Avoid EMB during menses because stromal breakdown can be misinterpreted as cell fragmentation and hemorrhage due to malignancy.


Procedure


The initial steps for endometrial biopsy are similar for the various methods. These are listed first (steps 1 through 8) and followed by descriptions of individual endometrial aspirators and specific instructions for their use. Confirm that the patient is not pregnant, if appropriate, before beginning the procedure.


1 The patient is placed in stirrups in dorsal lithotomy position (after the Pap smear is obtained, if indicated) and a bimanual examination is performed to determine the size and position of the uterus. The provider wears nonsterile gloves for this portion of the procedure.

2 Insert a large Graves speculum vaginally. Visualize the cervix and remove any mucus or debris.

3 Change into sterile gloves.

4 Prepare the cervix and vagina with povidone–iodine–soaked cotton balls using the ring forceps.

5 Perform an endocervical curettage in cases where neoplasm is suspected (see Chapter 137, Colposcopic Examination). Insert a Kevorkian curette without basket or a disposable curette into the endocervical canal. Manipulate the curette 360 degrees circumferentially around the entire canal, scraping in and out for two full rotations. Warn the patient about cramping. Collect all of the available material. Use ring forceps to collect any blood or secretions draining from the os. Place all the material on lens paper and then place it in formalin.

6 If insertion of the curette is difficult, use a single-tooth tenaculum to grasp the cervix at 12 o’clock. Traction on the tenaculum straightens the cervical neck and allows for easier endocervical curettage. Avoid grasping the 3 and 9 o’clock positions because of the presence of arteries at these points. Topical benzocaine gel (20%) or benzocaine spray (Hurricaine) may be applied to the tenaculum site to decrease pain. If used, the anesthetic needs to be in place several minutes before it has an effect. A submucosal injection of lidocaine works well (see explanation in Chapter 149, Loop Electrosurgical Excision Procedure for Treating Cervical Intraepithelial Neoplasia).

7 Once a gritty sensation is noted, remove the curette. Collect all tissue obtained and place it in formalin.

8 Proceed with EMB using one of the following techniques. With all endometrial biopsy techniques, insert the sterile sampling device through the cervical os without touching the vulva or vaginal walls. Do not touch or contaminate the part of the sampler that is placed into the uterus. Sterile gloves and speculum are not necessary if a “no-touch” technique is used.


Plastic Endometrial Aspirators (Pipelle or Endocell Endometrial Aspirator)


Disposable flexible endometrial sampling devices are the most popular method for EMB (Fig. 143-1A and B). The device is made of a clear, flexible polypropylene tube with an inner plunger. This functions as a piston and creates negative pressure when retracted quickly. A 2.4-mm distal side port allows for tissue sampling. The stiffer-tipped aspirators are more useful when cervical stenosis is present. More flexible types may be “stiffened” by placing them in a freezer for 10 to 15 minutes.



image


image

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Figure 143-1 A, Pipelle endometrial sampler. B, Depiction of Pipelle sheath and piston. C, The opening at the end of the Pipelle.


(Courtesy of CooperSurgical, Inc., Trumbull, Conn, with permission.)


The Pipelle samples 5% to 15% of the endometrial surface. Several types are calibrated and can be used to sound the uterus (6.5 to 10 cm is normal). Seventy-seven to 99% of specimens obtained using the Pipelle are adequate for histopathologic diagnosis.


The procedure for flexible endometrial aspirators follows, continued from previous steps 1 through 8.


9 Sound the uterus using either a calibrated flexible aspirator with the piston fully inserted or a metal sound (when using an uncalibrated product). Document the depth of the endometrial cavity (usually 6.5 to 10 cm). If the sound cannot be inserted, use a tenaculum to grasp the cervix at 12 o’clock. Outward traction straightens the cervical neck and allows the sound to pass through the cervical os. If the sound still will not pass, cervical dilation may be necessary (see Chapter 136, Cervical Stenosis and Cervical Dilation).

10 Introduce the aspirator, with internal piston fully inserted, into the endocervix. Pass it through the cervix and into the uterine cavity. Stop once the fundus is reached or resistance is encountered (Fig. 143-2A).

11 Stabilize the sheath with one hand while the piston is drawn back with the other hand. Negative pressure builds up in the lumen of the tube (Fig. 143-2B).

12 Rotate the sheath 360 degrees between the thumb and index finger. At the same time, withdraw the aspirator going from the fundus to the internal os. Most of the endometrial cavity can be sampled with a minimum of four complete in-and-out circumferential passes. As the aspirator completes a helical arc against the uterine walls, negative pressure within the sheath draws the sheared-off endometrial tissue through the distal port and into the lumen. The aspirator must be kept within the cervix or suction is lost (Fig. 143-2C).

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May 14, 2017 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Endometrial Biopsy

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