Introduction
When evaluating a patient with a mass in the head and neck, the fine-needle aspiration biopsy (FNAB) plays a critical role in the initial workup. It can help establish a diagnosis, among a wide variety of pathology, including infectious, benign, and malignant lesions. Needle biopsy, first popularized in the 1920s by Dr. Hayes Martin at Memorial Sloan-Kettering Hospital, has been used for more than 100 years. While he used large-bore needles under local anesthesia, it did not gain widespread acceptance in the United States until finer needles were available. Advances in cytology have made pathologists more comfortable in making a diagnosis, allowing head and neck surgeons to avoid unnecessary open biopsies.
FNAB is easily performed in the office, with high diagnostic accuracy, for both benign (95%) and malignant (87%) lesions. The technique can be used in a variety of sites in the head and neck, including the salivary glands, thyroid, and lymph node metastases. With a preoperative diagnosis, a definitive surgical plan prior to treatment can be established and discussed with the patient. FNAB is a minimally invasive technique, which allows for repeat sampling in the cases of a nondiagnostic specimen. It is safe, accurate, and cost-effective.
Fine-Needle Aspiration Biopsy for Thyroid Disease
Thyroid nodules, particularly in women, are a common finding. The American thyroid association (ATA) recommends a FNAB in all euthyroid and hypothyroid patients with suspicious lesions seen on a screening ultrasound ( Table 60.1 ). When evaluating thyroid lesions, the FNAB sample can be used for both histologic and molecular analysis. The specimens can also be stained and evaluated at the time of FNAB. This can provide both qualitative assessment of the specimen and often confirms the diagnosis. Thyroid cytopathology is typically reported using the Bethesda system ( Table 60.2 ). Cytopathology in benign disease has an estimated risk of malignancy less than 3%, while those that are suspicious for malignancy vary between 60% and 75%. Cytopathology in cases of malignancy is 99% accurate. Not all thyroid cancers can be diagnosed by FNAB. Follicular adenomas are indistinguishable from carcinomas on needle biopsy. Therefore the report of a follicular neoplasm only carries a 15% to 30% risk of malignancy.
| Sonographic Pattern | US Features | Estimated Risk of Malignancy, % | FNA Size Cutoff (Largest Dimension) |
|---|---|---|---|
| High suspicion | Solid hypoechoic nodule or solid hypoechoic component of a partially cystic nodule with one or more of the following features: irregular margins (infiltrative, microlobulated), microcalcifications, taller than wide shape, rim calcifications with small extrusive soft tissue component, evidence of ETE | >70–90 ∗ | Recommend FNA at ≥1 cm |
| Intermediate suspicion | Hypoechoic solid nodule with smooth margins without microcalcifications, ETE, or taller than wide shape | 10–20 | Recommend FNA at ≥1 cm |
| Low suspicion | Isoechoic or hyperechoic solid nodule, or partially cystic nodule with eccentric solid areas, without microcalcification, irregular margin or ETE, or taller than wide shape | 5–10 | Recommend FNA at ≥1.5 cm |
| Very low suspicion | Spongiform or partially cystic nodules without any of the sonographic features described in low, intermediate, or high suspicion patterns | <3 | Consider FNA at ≥2 cm Observation without FNA is also a reasonable option |
| Benign | Purely cystic nodules (no solid component) | <1 | No biopsy † |
∗ The estimate is derived from high volume centers; the overall risk of malignancy may be lower, given the interobserver variability in sonography.
† Aspiration of the cyst may be considered for symptomatic or cosmetic drainage.
| Diagnostic Category | Estimated/Predicted Risk of Malignancy by the Bethesda System (%) ∗ | Actual Risk of Malignancy in Nodules Surgically Excised, % Median (Ranges) † |
|---|---|---|
| Nondiagnostic or unsatisfactory | 1–4 | 20 (9–32) |
| Benign | 0–3 | 2.5 (1–10) |
| Atypia of undetermined significance or follicular lesion of undetermined significance | 5–15 | 14 (6–48) |
| Follicular neoplasm or suspicious for a follicular neoplasm | 15–30 | 25 (14–34) |
| Suspicious for malignancy | 60–75 | 70 (53–97) |
| Malignant | 97–99 | 99 (94–100) |
∗ As reported in The Bethesda System by Cibas ES, Ali SZ: The Bethesda System for reporting thyroid cytopathology. Am J Clin Pathol 132:658 – 665, 2009, http://dx.doi.org.easyaccess2.lib.cuhk.edu.hk/10.1309/AJCPPHLWMI3JV4LA .
† Based on the meta-analysis of eight studies reported by Bongiovanni M, Spitale A, Faquin WC, et al: The Bethesda System for reporting thyroid cytopathology: A meta-analysis. Acta Cytol 56:333 – 339, 2012. The risk was calculated based on the portion of nodules in each diagnostic category that underwent surgical excision and likely is not representative of the entire population, particularly of nondiagnostic and benign diagnostic categories.
Fine-Needle Aspiration Biopsy for Salivary Gland Disease
Lesions of the parotid and submandibular glands can be readily accessible to sampling by FNAB. While not every mass needs to be biopsied, any patient who presents with pain, facial weakness, numbness, or a mass in the parotid gland should have an FNAB. FNAB can also support a decision not to operate, in patients with a normal clinical examination and benign cytopathologic diagnosis. For example, a Warthin tumor has an exceedingly low malignant potential and in many cases can be observed. FNAB has very high overall accuracy (90% to 95%) at distinguishing benign from malignant lesions; however, it is not reliable at determining the malignant subtype and tumor grade. In some low-grade malignancies, such as acinic cell carcinoma, it can be misinterpreted as benign or non-neoplastic. Low-grade lymphomas can be missed and erroneously reported as inflammation. Therefore a negative diagnosis must be viewed within the clinical context. If there are suspicious clinical or radiographic findings, either a repeat FNAB or excisional biopsy should be considered.
Fine-Needle Aspiration Biopsy for the Mass in the Neck
All palpable masses in the neck, in both adults and children, can be safely assessed with an FNAB. Additionally, in most cases, ultrasound or computed tomography (CT) guidance can be used to localize and biopsy challenging or nonpalpable lesions. With lymphadenopathy, a specific diagnosis is obtained in 82% to 96% of cases. Cell blocks from the FNAB can be used for either immunohistochemistry or polymerase chain reaction (PCR)-based analysis. When a lymphoma is suspected, FNAB can rapidly establish a diagnosis and often avoid open neck biopsies. Improvements in immunologic methods have allowed an FNAB specimen to be sufficient to establish the diagnosis of lymphoma with at least two needle passes. In cases when an open biopsy is necessary to determine a gene rearrangement, reactive, inflammatory, and metastatic tumors are excluded, limiting the confirmatory diagnostic tests.
Key Operative Learning Points
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Distinguishing benign from malignant cervical masses, rapid assessment, potential avoidance of surgical intervention, low complication rates, and cost-effectiveness have made FNAB diagnosis of masses in the head and neck the standard of care.
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FNAB for thyroid follicular lesions cannot differentiate benign from malignant neoplasms.
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A cystic mass in the lateral aspect of the neck, in an adult, with squamous cells should be considered malignant until proven otherwise. These masses are usually a cystic form of metastatic squamous cell carcinoma, usually from the base of the tongue or tonsil, and should not be mistaken for a branchial cleft cyst.
Preoperative Period
History
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History of present illness
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Initial appearance of the mass in the head and neck
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Change in size over time
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Associated symptoms (pain, numbness, change in voice, facial weakness)
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Presence of lymphadenopathy beyond the head and neck
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Past medical history
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Radiation exposure
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Previous attempts at biopsy
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Previous treatment, particularly for cancer of the head and neck, or prior drainage of a cystic neck mass
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Family history
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Travel history
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Infectious history
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Medications
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Anticoagulants
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Physical Examination
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Palpable mass
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Mass characteristics (pain, fluctuance, overlying skin color changes)
Imaging
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None required for palpable masses
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Ultrasound-guided FNAB for nonpalpable masses and most thyroid nodules
Indications
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Masses in the neck (cystic and solid)
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Parotid lesions
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Thyroid nodules
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Palpable subcutaneous facial masses, including scalp
Contraindications
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There are no specific medical contraindications to the procedure.
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A small hematoma may occur if the patient is on anticoagulants. Even vascular masses including carotid body tumors may be biopsied with a fine-gauge needle using manual external pressure to minimize bleeding. Surgeons may prefer not to perform these biopsies if the patient is also anticoagulated.
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Preoperative Preparation
Informed consent should be obtained prior to performing an FNAB. Risks include a small amount of bleeding and/or bruise, infection, and a nondiagnostic specimen.
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