Gynecologic Needle Biopsy Workup

Generally, obtaining a coagulation profile is indicated prior to fine-needle aspiration (FNA) procedures, with the exception of a superficial biopsy.

Ultrasonography or other diagnostic imaging may provide additional information and may be used in conjunction with the FNA procedure. CT scan-guided FNA is a useful technique for biopsy of lesions that are not otherwise accessible.^[7] Also, intraoperative ultrasonography may be used to assist in directing FNA.

FNA is generally defined as use of a 22-gauge (or smaller) needle. The needle may vary in length from a standard 1- to 1.5-inch needle to a 6-inch spinal needle, optimally with a clear hub. A 10-mL Luer-Lok syringe with finger holes is usually sufficient (see image below).

The pistol grip used with a 20-mL syringe can assist in obtaining adequate aspiration with one hand, while the other hand is used to stabilize the tissue (see images below) Also, a needle guide can be used with a long needle to provide direction and prevent trauma to surrounding tissue. This is potentially useful with transvaginal or transrectal biopsies.

Specialty needles are sometimes used with image-guided FNA. A Chiba needle, as depicted in below, is used for deep-seated CT scan-guided biopsies. Images of this procedure are shown below, in which a retroperitoneal mass is biopsied.

With ultrasound-directed biopsies, a needle with enhanced sonographic visualization, such as the SonoVu US aspiration needle (shown below), can be used. The second image below depicts use of this method during a liver FNA biopsy.

FNA technique involves placement of the needle into the lesion in question and applying variable suction. A vigorous to-and-fro vertical motion is made to dislodge cells. The material should remain in the clear hub and suction should be released before withdrawing the needle to prevent aspiration into the syringe barrel. The number of passes is dictated by patient tolerance and sufficiency of the specimen. Having a pathologist present to examine the specimen microscopically helps determine adequacy.

After the needle is withdrawn, it is removed from the syringe; air is then drawn into the syringe, and the needle is replaced. The aspirate is placed on a slide that is then smeared with an opposing slide. An air-dried Diff-Quik–stained slide is prepared to determine the adequacy of sampling, and the remaining slides are fixed with alcohol and subsequently stained with Papanicolaou or hematoxylin-eosin stain. Results are generally available within 24 hours. For superficial biopsies, gentle pressure is typically sufficient to establish hemostasis.

Preparations for pelvic biopsy are simple. Patients should empty the bladder unless a full bladder is needed for ultrasound enhancement. If transrectal sampling is to be performed, administering an enema is prudent prior to biopsy.

The FNA specimen is processed for cytologic analysis; the interpretation is based on the principles of exfoliative cytology. In specific circumstances, with abundant material, a cell block can be made, which allows immunohistochemical staining and flow cytometry.

The pathologist should be aware of the possible diagnosis. If recurrent malignancy is of concern, the primary tumor type should be provided to the pathologist, preferably with previous histologic material available for comparison. In addition, the pathologist should be informed of prior therapy (ie, radiation), the anatomic site of the FNA, and the technique used to obtain it (ie, transvaginal, transrectal). For example, a finding of squamous cells from a transrectal FNA of a pelvic lesion suggestive of recurrent squamous cell carcinoma of the cervix following radiation may be more worrisome than a transvaginal FNA in which contamination of the specimen by vaginal squamous cells may occur. Also, a finding of cells that are not usually present in a particular anatomic location (eg, squamous cells in a lymph node) may provide valuable information for the pathologist.

The specimen is first assessed for adequacy. A hypocellular specimen is often inadequate for interpretation. However, this result may be expected from aspiration of a postoperative lymphocyst, so communication with the pathologist is important. Adequate samples are generally interpreted as positive, suspicious, or negative. FNA specimens positive for malignancy are reliable, with a false-positive rate of less than 1%. Suspicious or negative results are more problematic; further assessment, including open biopsy, may be necessary after review with the pathologist.

The following image depicts an FNA aspirate that is positive for recurrent squamous cell carcinoma. Note the large pleomorphic cells with a high nuclear/cytoplasmic ratio, "tadpole" shape, and glassy cytoplasm. Large syncytial groups may be seen, with intercellular bridges and associated keratin pearls.

The following image shows an FNA aspirate positive for metastatic ovarian adenocarcinoma. Here, cellular adherence is seen with a 3-dimensional configuration and high nuclear/cytoplasmic ratio. Pseudoglandular formation may also be observed.

Complications of fine-needle aspiration (FNA) are rare, with the incidence of major complications reportedly well below 1% and generally in the range of 0.05%. A review of the hazards associated with FNA in general reported a mortality rate of approximately .006%, or 1 death per 15,000 procedures.^[8] The most common cause of death was hemorrhage. Bleeding from CT scan-guided FNA of retroperitoneal adenopathy is reported as occurring in less than 1% of cases, despite the proximity to great vessels.^[7] Data specific for gynecologic malignancy indicate an overall complication rate of less than 1%.^[2] Another concern relates to needle-tract seeding of malignant cells. This risk is extremely low, with reported incidence of 0.009%.^[9]

The positive predictive value of fine-needle aspiration (FNA) approaches 100%, with an extremely low false-positive rate (< 1%). The false-negative rate is variable but approaches approximately 30%, with a negative predictive value of 50-75%. The specificity of the test is essentially 100%, while its sensitivity is about 65%. The overall accuracy of FNA in gynecologic malignancies is about 90%.^[10]

Accuracy is affected by the specific location of the lesion and associated degree of hypocellularity. Deep lesions requiring imaging guidance reportedly have a lower rate of hypocellularity than superficial lesions. In addition, the accuracy of FNA in a field of prior radiation is reduced secondary to fibrosis and associated hypocellularity and to difficulty in distinguishing malignancy from radiation effect cytologically. Generally, negative FNA results warrant consideration of either a true-cut or open surgical biopsy, which increases the potential for morbidity and mortality.

In both the hospital and ambulatory setting, best practice is achieved in a multidisciplinary team environment that includes those responsible for the performance, interpretation, and correlation of the tests and for patient care. However, one clinician should take the responsibility for coordinating the care and communicating the results to the patient. Using the team approach provides the best opportunity for continuous improvement in quality of care.