Disclaimer: The information contained within the Grand Rounds Archive is intended for use by doctors and other health care professionals. These documents were prepared by resident physicians for presentation and discussion at a conference held at Baylor College of Medicine in Houston, Texas. No guarantees are made with respect to accuracy or timeliness of this material. This material should not be used as a basis for treatment decisions, and is not a substitute for professional consultation and/or peer-reviewed medical literature. Fine Needle Aspiration of Thyroid Nodules The patient today is a 59-year-old Hispanic female. She presented to the Ben Taub Otolaryngology Clinic with a left-sided neck mass, painless and slowly-growing over the last six months. She had no symptoms to suggest hypo- or hyperthyroidism and no respiratory difficulty or hoarseness. Physical examination: We found a 2 cm neck mass in the left side of her neck. She had no exophathlmos. There was no erythema, warmth, or indications of infection. Her voice was very strong. Her white blood cell count and a thyroid function test were all within normal limits. As per protocol, a fine needle aspiration was performed on this mass, and it came back as suspicious for malignancy. What I want to do is come back to this particular patient’s slides at the end of the talk and we’ll use what we’ve learned today to analyze them. Needle aspiration has been in use for about 80 years. It was first used in the United States by Dr. Martin and his colleagues at the Sloan-Kettering Cancer Institute in New York. Since there was initially not much data on results, American pathologists and physicians were very reluctant to use it. But many of the Europeans and the Swedes did research and publish on it during the ‘50s and ‘60s. By the end of the 1970s FNA was beginning to gain widespread acceptance in the United States and was on its way to becoming the standard of care that it is today. The main goal of FNA is not necessarily to provide you with a definitive diagnosis of your tissue. It can do that, and it oftentimes does, but the main goal is to keep people who don’t need surgery off the operating room table. That can’t be overstated enough. It’s also fairly safe and cost effective. It can be performed by a variety of doctors—radiologists, clinicians, pathologists—it can even be performed as an office procedure in an outpatient setting. Unfortunately, the success of the procedure can be very highly related to operator experience, but as more and more people are gaining more and more experience with it, that factor is becoming less important. It is performed using a very small needle, usually a 27-gauge needle. You don’t need much local anesthetic for it, and it is inserted into the lesion, either by palpation or under image guidance. Cellular material is aspirated into a syringe and expelled onto a slide and a cytologic diagnosis is rendered. FNA gives us cytologic diagnoses. It looks at individual cells and cellular structures, not at macrotissue architecture, like a histologic specimen would. This is an example of how you would perform this on a thyroid nodule. The other clinician is palpating a thyroid nodule, inserting the needle into it, and aspirating the cellular material. It can also be performed under ultrasound guidance, as shown here. You see a needle inserted into a target lesion. There is the needle tip in the lesion; and on the right is the material that was aspirated from it. This can be very useful for getting smaller lesions that you can’t necessarily palpate. In FNA, compared to core needle biopsy, there is less concern for tumor seeding. Core needle biopsies tend to use 16 and 18-gauge needles. They will require a local anesthetic, and are some concern for tumor seeding with core needle biopsies. Obviously, it is a large needle; it’s going to be a little less comfortable. There is a higher risk of bleeding, and it will be a little more expensive. Excisional biopsy is another option. That’s a surgical procedure requiring, again, some sort of anesthetic. It can be very uncomfortable for the patient at times, but it does afford a histologic diagnosis, a big advantage of an excisional biopsy over fine needle aspiration. With regards to the thyroid, FNA has become considered the gold standard for diagnosing nodules and screening patients for surgery. When it provides a diagnosis, the accuracy is extremely high—95 to 98 percent in most studies. The drawback is that up to a quarter of the specimens that you receive will be labeled as nondiagnostic or inadequate for analysis, meaning there simply aren’t enough cells to provide a diagnosis. It can also be very difficult with very small nodules, because you have a hard time getting the needle into it, or for very large ones because you can have sampling errors as the needle doesn’t get the right part of a nodule to give a diagnosis. This is the histologic appearance of normal thyroid tissue. The thyroid is a very specialized epithelial structure arranged into lakes of colloid tissue referred to as follicles. The colloid basically reserves the thyroid hormone. You can do special stains, as you see in the bottom left, to identify the parafollicular or C cells. It looks quite different under fine needle aspiration. On the left, you can see that sometimes you get the appearance of follicular architecture, but it isn’t as clear or well-defined as it is in histology. What you’re interested in is what you see on the right, which are very normal, round cells arranged in what is described as a honeycomb pattern. They’ve got great dense granular cytoplasm, and they are very, very smooth. They are round; they are regular, and you can very rarely visualize the nucleus on normal thyroid cells. FNA will provide you with four different categories of diagnoses when you look at this—benign disease, malignant disease, indeterminate or suspicious disease, and non-diagnostic or unsatisfactory disease. This top category is what I want to talk about first—the benign diseases. This is really where FNA has had its biggest clinical impact, is keeping these patients off the operating table. In the era before FNA, these patients would present to us with thyroid nodules, they would go to the operating room and they would get their thyroids taken out. Nowadays, we can do an FNA, we can diagnose thyroiditis. We can diagnose for the benign conditions and, fortunately, prevent these people from having an unnecessary operation. Now, this is the image of thyroiditis on fine needle aspiration. As we get into the thyroid cytology, what I hope to accomplish is to give everyone a better appreciation really for what the pathologists are looking at when they give us these reports—being able to read them and know what a nuclear groove is, know what the lymphocytes look like, and get a better appreciation of what the cytologic findings actually are for the diagnoses. The key finding in thyroiditis. You’ll see a normal-appearing thyroid follicle but you’ll see an abundance of lymphocytes, and that’s really the key to the diagnosis with thyroiditis. Hürthle cells are the basically abnormal cells found in inflammatory conditions and in neoplastic conditions, and their diagnostic criteria is a large nucleus with a prominent nucleolus in abundant dense cytoplasm. Next, is the colloid nodule or the cyst. This is another benign condition. It is very common, and the key cytologic finding is the density of the colloid and the density of the follicles. On the left, you see a normal FNA. You see a normal density of follicles; you see a moderate amount of colloid. On the right, you see one follicle and a lot of colloid; but the follicle, more importantly, is normal-appearing. It has normal regular cells with no cytologic abnormalities. This is what a colloid nodule looks like. It is one follicle producing much more colloid than it should. The next category and the one of more clinical relevance for us as surgeons is the malignant disease category. These are both differentiated and undifferentiated thyroid cancers. Papillary carcinoma. On the right we see a histologic section of papillary carcinoma with the classic clear nuclei and finger-like projections. These finger-like projections, as seen on the left in the FNA specimens, can indeed be seen on FNA. What you want to look at to diagnose papillary carcinoma is the individual cells. This is a close-up of one of those finger-like projections, and it shows the key hallmarks of what the cytopathologists are seeing when they give you this diagnosis. You’re seeing nuclear pseudoinclusions. These are clear, round spots inside the nucleus of cells. You’re seeing fine chromatin, described as ground glass. It is indicative of highly active DNA. In conjunction with a highly active nucleus, the site of the nuclear membrane will be forming lots of vacuoles for transport, and it generates nuclear grooves. If you can imagine, if you rotated the cell a little bit in three dimensions, that nuclear groove that folds and bends in the cytoplasm is going to create this dark line across the nucleus, described as nuclear grooves. That’s how you diagnose papillary carcinoma. And I guess no discussion of that would be complete without discussing psammoma bodies. Psammoma bodies are fairly nonspecific findings that are thought to arise in calcificatons of nephrotic tumor cells, and they are found in a variety of inflammatory and neoplastic conditions, but when you find it in a specimen that is known to be from thyroid, it can be fairly diagnostic for papillary thyroid carcinoma, although they are only found in about 50 percent of the specimens you submit. Medullary carcinoma can also be diagnosed definitively from fine needle aspiration. You see coarse granular cytoplasm, just like in papillary carcinoma; but more importantly, you see a round and oval-appearing nuclei that are eccentrically placed. You will see them described as resembling plasma cells. This really is the key characteristic of diagnosis of medullary carcinoma—these thyroid follicular cells that look like plasma cells. And you can also do calcitonin immunostain to identify the parafollicular cells. Anaplastic carcinoma can also be identified with fine needle aspiration. We see pleomorphic giant cell nuclei, and you see lots of mytonic bodies with coarse, dense chromatin indicative of highly active cells. They are very irregular, very amorphous, with large mitotic bodies. And, you can also do a stain for cytokeratin. The last thing to discuss with regards to carcinoma is that it can be diagnosed as malignant disease. This is an example of an adenoid cystic carcinoma that metastasized to the larynx. You see a cystic structure with a very thick basement membrane, and this was able to be diagnosed from a FNA of a thyroid nodule. The treatment can be fairly straightforward. They obviously need thyroidectomies. But the category that tends to create more problems for us as clinicians is the category of indeterminate or suspicious lesions. Now, the key thing that I want to drive home about the nondiagnostic and inadequate specimens is that it is not nondiagnostic. And the word “indeterminate” can even be sort of a misnomer. With regards to these follicular neoplasms, Hürthle cell neoplasms, FNA really functions as a screening tool. You get a diagnosis of a follicular lesion and what the FNA diagnosis is telling you is that this is not a benign condition. It is telling you it is a neoplastic condition assuming that the patient probably needs surgical treatment, and so it is accomplishing the goal of FNA. Even though it is not giving you a definitive diagnosis, it is telling you this is not a benign condition and it does need surgery, and that is the overall goal of FNA—to identify surgical patients. To identify and classify follicular lesions, suspicious neoplasms versus benign goiters, look at the amount of colloid, and the cellularity of the specimen along with the shape and architecture of the follicles. This graph describes what the pathologists are looking at. As colloid goes from more to less and cells go from less to more, you end up with the higher diagnosis of malignancy. Zone 3 is the follicular nodules—these are the follicular neoplasms that you get on FNA. These have a 40 percent chance of being neoplastic - high enough to warrant surgical excision. Follicular neoplasm. On the left, you see a follicular neoplasm; on the right, you see a normal thyroid FNA. The differences become fairly obvious. You see on the left very sparse colloid; and on the right, dense and a normal amount of colloid. Then, on the left, there are scattered microfollicles.These are follicles of 10 to 12 cells each, as opposed to 25 to 30 in normal follicles. On closer examination, again, we’re looking at cytologic cellular architecture, nuclear overlap on the left, a little nuclear overlap on the right; nuclear size variation in the neoplasm, and little nuclear size variation in the regular cell. The reason it’s called suspicious or indeterminate is that you obviously can’t diagnose adenomas on fine needle aspiration versus carcinoma, because to diagnose a carcinoma you have to see capsular invasion or vascular invasion. On the right is the benign colloid nodule that we talked about earlier. On the left, the follicular neoplasm. This again indicates what the pathologists are looking at--the differentiation of a benign nodule from a suspicious lesion. Dense colloid and normal sparse colloid, possibly neoplastic. Microfollicles, neoplastic; macrofollicles, not neoplastic. And again, nuclear overlap and size variation as indications of abnormal cellular activity. Hürthle cell neoplasms can also be considered suspicious or indeterminate because you can’t see capsular or vascular invasion on the FNA. Hürthle cell neoplasms are characterized as microfollicles, lined by large cells. Under the microscope, you see upper linings of Hürthle cells, which as described, large nucleus, single prominent nucleolus, abundant dense cytoplasm. As mentioned earlier, Hürthle cells also can be an indication of thyroiditis and inflammation, and when a pathologist is characterizing to you whether or not this is a Hürthle cell neoplasm vs. a lymphocytic thyroiditis, they are looking for lymphocytes, but they are also going to be looking at the amount and preponderance of the Hürthle cells. The more Hürthle cells, the more likely it is to be a neoplasm. The one that really creates a lot of headaches for pathologists and where some of your false-positives can come from is a follicular variant of papillary carcinoma. This basically is papillary carcinoma cells arranged in a follicular architecture. On the left you see a follicular neoplasm, on the right papillary carcinoma; and they look very similar at initial analysis. But, if you pay close attention, you’ll see the cells in the follicle have got the nuclear inclusions from ground glass cytoplasm and nuclear grooves, suggestive of papillary thyroid carcinoma. So, what do you do? If you get a report of suspicious or indeterminate, it is telling you that this is probably a neoplastic lesion. It is most likely not a benign lesion and you can proceed then with lobectomy or isthmusectomy. Some clinicians in some studies suggest re-biopsy, but a full discussion of processing is beyond the scope of this presentation. But, you can do a lobectomy or an isthmusectomy and then get your diagnosis of carcinoma or adenoma, and even adenomas have a small risk of becoming carcinomas and need surgical excision. The last category is a nondiagnostic or unsatisfactory. Up to a quarter of these come back as nondiagnostic. The reason it is nondiagnostic is because there just aren’t enough cells to make a diagnosis. A take-home point about nondiagnostic specimens is that you really need to re-aspirate them. You wait about three months for the inflammation from needle insertion to go down, and you’ll get a diagnosis in up to two-thirds of the re-aspirations. Ultrasound guidance is, of course, used in FNA. It was first used in 1987. It has been used more frequently since then, especially with the high resolution ultrasounds that we now have. It is very useful for getting very small lesions, 2 mm, and it can also help us find out or get better diagnoses of large lesions in areas that are complex and cystic. You can find out exactly where you want to put the needle. This is an example of a thyroid ultrasound. There is the lesion. There is the course of the needle that the pathologist would target. There is the needle tip in the lesion, and he aspirates some of the material out. The question becomes do you want to do an ultrasound-guided FNA on all lesions, and the jury is still out on that. To provide some data, This is a study done in 1998. They did about 500 fine needle aspirations, and they found that with ultrasound guidance, you can get obviously much, much smaller lesions, and, of importance, the unsuccessful biopsy rate drops almost in half, or more than half, with ultrasound-guided FNA versus palpation-guided FNA. But, ultrasound-guided FNA does cost about three times more than palpation-guided FNA. So, with regard to thyroid lesions, FNA has a very small false-positive; and a very small false negative rate. It is very accurate and provides us with substantial improvement in cost and efficiency. It has given us a 25 percent reduction in overall cost and saves us almost $2000 per patient. It has also resulted in 50 percent fewer thyroidectomies performed; and of great interest, we now have a much higher malignancy and cancer yield in the thyroidectomies that we perform. There are some limitations. You can have resultant tumor necrosis from fine needle aspirations, reported in 40 to 45 cases in the literature. There is a high correlation with operator experience, and you do have the risk of nondiagnostic yield. Then, there’s the gray area of what to do with your suspicious lesions, and there is the possible pitfall of follicular variant papillary thyroid carcinoma. Overall though, it is a very good technique. Now, taking what we have just talked about and coming back to our case presentation. This is what our patient’s FNA looked like. Now, what we see here is a follicular orientation of cells; but if you look really closely at a couple of the cells, for example, the one circled, it has a nuclear groove in it, and this cell had a nuclear pseudoinclusion in it. The diagnosis came back from the pathologist as a follicular orientation, suspicious for papillary carcinoma. They weren’t able to diagnose it, but it was suspicious for papillary carcinoma. The patient was taken to the operating room where a thyroid lobectomy was performed. Permanent section showed papillary carcinoma. The patient received a total thyroidectomy and has since done very well. Shown here are the classic clear nuclei that you see in papillary carcinoma. Lastly, there are some immunologic stains. Calcitonin and cytokeratin have gained widespread acceptance for medullary carcinoma and aplastic carcinoma respectively. There really isn’t much there to help further identify papillary carcinomas and follicular carcinomas on the FNAs. So, in summary, FNA is an invasive and very specific technique for diagnosing thyroid lesions. You can get suspicious or indeterminate lesions, but remember, this is not nondiagnostic. It is a diagnosis that provides you guidance for further surgical treatment. When you get a nondiagnostic one, you can re-aspirate it and you will get a diagnosis in about two-thirds of the cases. FNA has greatly helped us reduce the cost of the care for patients. It has helped us get out more cancers; and when we do go to the operating room, we get a higher percentage of cancers. Case Presentation M.H. is a 49-year-old Hispanic woman with no significant past medical history who presented to the Ben Taub Otolaryngology clinic with a left-sided neck mass that she had noticed about 6 months ago. It was growing slowly and causing mild dysphagia, but was not causing any hoarseness or difficulty breathing. She denied any fever, weight loss, or night sweats. There had been no abrupt change in weight or appetite, and the patient did not suffer from hyperactivity, restlessness, anxiety, or hot/cold intolerance. She also denied otalgia, headache, visual changes, hearing loss, vertigo, otorrhea, tinnitus, changes in smell and had no other complaints related to her ears, nose, or throat. There was no past history of autoimmune diseases, no prior radiation exposure or radioactive iodine exposure. There was no family history of head and neck malignancy. The patient did not smoke. Physical exam revealed a healthy appearing Hispanic woman with normal pulse and blood pressure and a 2cm firm nodule on the left side of her thyroid. The mass was rubbery, nonmobile, and nontender. There was no warmth, erythema, or purulence. There was no cervical LAD, and there were no other neck masses. There was no exophthalmos; the oropharynx was clear with soft floor-of-mouth and base-of-tongue; the tympanic membranes were clear; and the nasal passages were clear to anterior and posterior rhinoscopy. Flexible laryngoscopy revealed a normal larynx with mobile true vocal cords bilaterally. WBC, TSH, Free T4 and serum calcium were normal. A chest x-ray was normal. A thyroid ultrasound showed a heterogenous mass in the left thyroid lobe and a 3mm nodule in the right thyroid lobe with no cervical lymphadenopathy. Fine needle aspiration revealed a follicular neoplasm with changes suspicious for papillary carcinoma. The patient underwent a left thyroid lobectomy. Frozen sections were inconclusive, but permanent section analysis revealed follicular variant of papillary thyroid carcinoma. The patient underwent a completion thyroidectomy 10 days later and has since done very well. Bibliography: Amedee RG, Dhurandhar NR. Fine-needle aspiration biopsy. Laryngoscope 2001;111:1551-7. Bahar G, Braslavsky D, Shpitzer T, Feinmesser R, Avidan S, Popovtzer KS. The cytological and clinical value of the thyroid “follicular lesion.” Am J Otolaryngol 2003;24:217-20. Baloch Z, LiVolsi VA, Jain P, Jain R, Aljada I, Mandel S, et al. Role of repeat fine-needle aspiration biopsy (FNAB) in the management of thyroid nodules. Diagn Cytopathol 2003;29:203-6. 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