Micronucleus scoring in liver fine needle aspiration cytology

C.‐H. Wen, C.‐H. Lin, S.‐C. Tsao, Y.‐C. Su, M.‐H. Tsai and C.‐Y. Chai
Micronucleus scoring in liver fine needle aspiration cytology Objective: This study evaluated the role of the micronucleus (MN) in liver fine needle aspiration (FNA) cytology. Methods: Histological features of 75 cases of hepatocellular carcinoma (HCC), of which 25 were well differentiated, 37 moderately differentiated and 13 poorly differentiated, and 58 benign hepatic lesions (total, 133 cases) were correlated with MN expression observed in FNA smears reported as benign (n = 40), atypical (n = 14), suspicious (n = 30) and malignant (n = 49). Results: Stepwise increases in the MN score (0.4 ± 0.6, 1.2 ± 1.3, 6.3 ± 4.2 and 14.3 ± 8.8) correlated with the degree of cytological abnormality: benign, atypia, suspicious and malignant, respectively. The mean MN scores for well‐, moderately and poorly differentiated HCC were 5.4 ± 2.2, 11.5 ± 4.5 and 24.9 ± 9.1, respectively, which was significantly different between malignant and suspicious (P < 0.0001), between suspicious and atypical (P = 0.008) but not between atypical and benign. The MN scores differed significantly between all degrees of differentiation of HCC and between the HCC and benign hepatic lesions (P < 0.0001). High sensitivity, specificity and accuracy of liver FNA for diagnosing HCC (96%, 98%, and 96%, respectively) were obtained at a cutoff of three for the MN score. Conclusions: The MN score is an effective HCC biomarker and has a good potential use as an ancillary tool for diagnosing HCC using FNA cytology.     

Peripheral endothelial cells are not reliable in differentiating primary benign and malignant hepatocellular lesions in fine needle aspirates of the liver

The distinction of hepatocellular carcinoma (HCC) from benign lesions of the liver in fine needle aspiration (FNA) specimens can be problematic. In an attempt to separate well-differentiated HCC from benign hepatocellular lesions, the presence of tissue fragments displaying peripheral endothelial cells (PE) has been proposed in a previous study as a useful feature in favour of malignancy. In this study, we evaluated slides from 59 cases of liver masses undergoing FNA (19 HCC, 40 benign) and evaluated them for the presence of tissue fragments containing PE. We found that 90% of cases of HCC contained tissue fragments in which PE were either focally present or abundant. However, 68% of cases containing only benign hepatocytes also contained tissue fragments in which PE were at least focally present. In addition, it appears that within the group of benign lesions, the presence of PE was related to the overall cellularity of the specimen rather than the specific nature of the lesion. Thus, the presence of PE in tissue fragments does not, in isolation, appear to be a useful morphological feature for the separation of benign and malignant hepatocellular lesions in FNA material.     

Role of CD10 immunochemistry in differentiating hepatocellular carcinoma from metastatic carcinoma of the liver

Background:  Differentiation of hepatocellular carcinoma (HCC) from metastatic carcinoma in liver may be difficult on fine needle aspiration cytology (FNAC), especially when both appear as moderate to poorly differentiated tumours. A panel of immunocytochemical stains is frequently used in case of diagnostic difficulty. Recently, CD10 immunostain with a canalicular staining pattern has been shown to be a specific marker for hepatocytic differentiation.
Objective:  The present study was designed to assess the value of CD10 immunostain in distinguishing HCC from metastatic carcinoma in material obtained by FNAC of liver masses.
Materials and methods:  Formalin-fixed, paraffin-embedded cell blocks of 22 cases (7 cases of HCC and 15 cases of metastatic carcinoma), direct acetone-fixed smears and destained smears of 28 cases (18 cases of HCC and 10 cases of metastatic carcinoma) prepared from FNAC of the liver were immunostained using monoclonal antibody against CD10.
Results:  Seventeen (68%) of twenty-five cases of HCC were positive for CD10 with a canalicular staining pattern. Among them 7 (70%) of 10 cases were well-differentiated HCC and 10 (66%) of 15 cases were moderate to poorly differentiated HCC. Of 25 cases of metastatic carcinoma, four (16%) were positive for CD10 with a cytoplasmic (three cases) and membranous staining (one case) pattern.
Conclusion:  CD10 immunostaining is useful in discriminating HCC and metastatic carcinoma of the liver and is easily applied on cell blocks as well as FNAC smears.     

Distinction between colloid nodules and follicular neoplasms of the thyroid. Further observations on cell blocks

The differentiation between colloid nodules and follicular neoplasms may be difficult in lesions yielding only microfollicles by fine needle aspiration (FNA). In a retrospective study of 35 follicular lesions, the FNA smears and cell blocks and the excised specimens were reviewed for possible distinguishing features. Columnar cells lining follicles and prominent sinusoidal stroma were seen only in follicular neoplasms; these were more easily appreciated in the cell blocks. Nuclear features and fibrosis were not helpful because they were found in both groups of lesions. Attention to the nuclear morphology was important, however, for the diagnosis of the follicular variant of papillary carcinoma. A repeat FNA might be helpful in obtaining hyperplastic papillae and fragments of dilated follicles for a diagnosis of colloid nodule in half of the cases. A few lesions with predominant microfollicular patterns were even problematic to diagnose on the excised specimens.     

Can abundant colloid exclude oncocytic (Hürthle cell) carcinoma in thyroid fine needle aspiration? Cytohistological correlation of 127 oncocytic (Hürthle cell) lesions

Objective:  The objective of the present study was to find out whether the presence or absence of certain cytological features can exclude oncocytic (Hürthle cell) carcinoma in thyroid fine needle aspiration (FNA) to minimize unnecessary surgery. Methods:  Over a 17‐year period, 127 hypercellular, oncocyte‐exclusive, lymphocyte‐absent aspirates obtained via ultrasound‐guided FNA with on‐site assessment had histology slides for review. The presence or absence of six cytological features (microfollicular arrangement, discohesive single cells, small cell dysplasia, large cell dysplasia, transgressing blood vessels and colloid) and one histological feature (macrofollicular component) were determined for each case independently by two cytopathologists. Results:  Histology showed 12 (9.4%) cases of Hashimoto thyroiditis, 23 (18.1%) oncocytic adenomatoid nodules in nodular goitre, 66 (52.0%) oncocytic adenomas and 26 (20.5%) oncocytic carcinomas (13 minimally invasive without angioinvasion, six minimally invasive with angioinvasion, seven widely invasive). Histologically, a macrofollicular component was present in seven of 26 (26.9%) oncocytic carcinomas, including one case with abundant thin colloid. A microfollicular arrangement, discohesive single cells, small cell dysplasia, large cell dysplasia and transgressing vessels were present in oncocytic carcinoma, oncocytic adenoma and oncocytic adenomatoid nodules in nodular goitre. Conclusions:  A macrofollicular component is frequently present in oncocytic carcinoma, oncocytic adenoma and oncocytic adenomatoid nodules in nodular goitre. None of the cytological features studied, including abundant colloid, can exclude oncocytic carcinoma. Oncocytic carcinoma can only be excluded by thorough histological examination of thyroidectomy specimens. A molecular marker is needed to triage oncocytic lesions in thyroid FNA.     

Accuracy of cytology vs. microbiopsy for the diagnosis of well-differentiated hepatocellular carcinoma and macroregenerative nodule. Definition of standardized criteria from a study of 100 cases

OBJECTIVE: To determine the accuracy of ultrasound (US)-guided fine needle aspiration (FNA) for the diagnosis of well-differentiated hepatocellular carcinoma (wd HCC) and macroregenerative nodule (MRN) and to identify the most useful cytologic and histologic criteria to distinguish between those two diagnoses. STUDY DESIGN: Cytologic and histologic specimens of 50 wd HCC and 50 MRN were reviewed blindly and the diagnosis compared to the final clinical diagnosis. Twenty-eight cytologic and 25 histologic criteria were examined and subjected to statistical analysis. RESULTS: Among 100 cases studied, the final diagnosis was available for 43. In those 43 cases, combining analysis of cytologic and histologic specimens, the sensitivity of US-guided FNA was of 75% and the specificity 100%. Cytologic analysis was better than isolated histologic analysis, with a sensitivity of 75% vs. 68%, respectively. Sensitivity of cytologic diagnosis was lower for smaller nodules and for those located in poorly accessible hepatic segments. With the use of stepwise logistic regression analysis, four cytologic features (increased nuclear/cytoplasmic ratio, cellular monomorphism, nuclear crowding, loss of bile duct cells) and four histologic features (increased nuclear/cytoplasmic ratio, decreased Kupffer cells, cellular monomorphism, increased trabeculae thickness) were identified as predictive of HCC.     

Ultrasonography in the study of hepatocellular carcinoma in woodchucks chronically infected with WHV

The woodchuck hepatitis virus (WHV)/woodchuck system is studied as animal model of human hepatocellular carcinoma (HCC) induced by chronic hepatitis B virus infection. The aim of the present study was the evaluation of ultrasound (US) liver examination in woodchuck as a routine method to detect HCC nodules and to follow their growth. Sixteen woodchucks were included in the study. US liver examination was carried out in all animals using a 5 MHz convex scanner. Macroscopic and microscopic examinations were performed to evaluate the US findings. The lower limit of nodule detection by US examination was a diameter of 5 mm. Macroscopic and microscopic examinations confirmed US findings in 14 of 16 animals (86.6%). No false negative results were obtained. Increase of nodule size was faster in the early phase of tumour growth. Small nodules (16 +/- 5 mm) appeared as hypoechoic lesions with well-defined margins and homogeneous structure. Large nodules (42 +/- 19 mm) appeared as hyperechoic lesions with irregular margins, heterogeneous or of mixed pattern; microscopical examination showed different degrees of necrosis, inflammation and fibrosis inside these latter neoplasms. The hepatitis reaction was conspicuously more severe around HCC nodules. No fibrosis and/or cirrhosis were found in normal liver parenchyma surrounding tumour nodules. On the whole, US appears to be helpful in the diagnosis of woodchuck HCC even at an early stage. Serial US evaluation can be used to study the growth rate of tumour nodules during natural history or experimental HCC treatments in woodchuck.     

Role and accuracy of rapid on‐site evaluation of CT‐guided fine needle aspiration cytology of lung nodules

A. Fassina, M. Corradin, D. Zardo, R. Cappellesso, F. Corbetti and M. Fassan
Role and accuracy of rapid on‐site evaluation of CT‐guided fine needle aspiration cytology of lung nodules Objective: To prospectively investigate the role of trans‐thoracic fine needle aspiration cytology (FNA) and the value of rapid on‐site evaluation (ROSE) in the clinical management of patients with pulmonary nodules/masses. Computed tomography (CT)‐guided FNA is commonly employed for the diagnosis of lung lesions although its position in the diagnostic work‐up is still a matter of debate. Methods: We reviewed 311 patients (211 males and 100 females, mean age 69.5 years) admitted to the University of Padova from 2004 to 2008, correlating the results of cytology with the available histological findings obtained from biopsies, surgery or autopsy. Results: Smears were adequate in 305 cases (98%) and inadequate in six (2%); a diagnosis of malignancy was achieved in 263 cases (86.2%); 39 cases (12.8%) were classified as non‐malignant; and three cases (1%) were classified as suspect for malignancy. When correlated with histology, FNA with ROSE discriminated malignant versus non‐malignant lesions (Cohen’s kappa 0.78), with three false negatives (sensitivity 96.3%, specificity 100%). Moreover, a satisfactory overall agreement of 71.4% was achieved in differentiating the cancer histological types. Pneumothorax occurred in 13 cases, haemoptysis in four, and chest pain in three. A single aspiration was sufficient in 79.6% of patients; two aspirations were needed in 17.4% and three in 3%. The low complication rate was related to the limited number of aspirations needed due to ROSE. Conclusions: FNA with ROSE is a safe and useful tool in the diagnostic work‐up of lung cancer patients, with no contraindications to its use as the first diagnostic procedure for all patients with peripheral lung lesions. FNA with ROSE should be reconsidered in the guidelines for diagnosing and managing lung cancer.     

Fine needle aspiration of focal liver lesions

Fourteen percutaneous fine needle aspirates (FNAs) of focal liver lesions performed under ultrasound guidance at the Sultan Qaboos University Hospital (SQUH), Oman, between January 1991 and October 1992, are presented. Ten of these were cytologically diagnosed as hepatocellular carcinomas (HCC). the patients' ages ranged from 50 to 70 years and eight of these were males. the important diagnostic cytological criteria of HCC were found to be increased nucleocytoplasmic (N/C) ratio, trabecular pattern, atypical naked nuclei, bile production by malignant hepatocytes and absence of bile duct epithelium. Carcinoembryonic antigen (CEA) positivity of bile canaliculi by cross-reaction with biliary glycoprotein I (BGP I) made possible the differentiation of HCC from metastases. We stress the importance of cell blocks as these often constitute microbiopsies. Ultrasound-guided FNA of focal liver lesions is recommended as a simple, easy and quick procedure.     

Follow‐up of atypia and follicular lesions of undetermined significance in thyroid fine needle aspiration cytology

N. Dincer, S. Balci, A. Yazgan, G. Guney, R. Ersoy, B. Cakir and G. Guler
Follow‐up of atypia and follicular lesions of undetermined significance in thyroid fine needle aspiration cytology Objective: To report our experience of atypia of undetermined significance (AUS)/follicular lesion of undetermined significance (FLUS) rate and outcome. Methods: Among 7658 patients with 19 569 nodules, 524 (2.7%) nodules were diagnosed as AUS/FLUS on fine needle aspiration (FNA). After exclusion of patients with simultaneous nodules that were suspicious for follicular neoplasm or malignancy or that were malignant, 368 (4.8%) patients were diagnosed as AUS/FLUS. The outcome of 146 patients who had undergone surgery or repeated fine needle aspirate at the time of preparation of this study was evaluated. The original FNAs were matched to repeated FNAs and thyroidectomy or diagnostic lobectomy specimens. Results: Seventy‐two (19.6%) of the 368 patients had directly undergone surgery, either a lobectomy or a thyroidectomy: of these, 27 (37.5%) had neoplastic nodules (21 were malignant). Seventy‐four (20.1%) of the 368 patients had repeat FNA. On second FNA, 47 of 74 (63.5%) were benign, three were suspicious for follicular neoplasm, one was malignant and 23 (31.1%) were non‐diagnostic. Four patients had a third FNA: two were AUS/FLUS, one was malignant and one non‐diagnostic. One patient had a fourth FNA, which was diagnosed as AUS/FLUS. Sixteen (21.6%) of 74 patients with repeat FNA had surgery: three of these had neoplastic nodules (two were malignant). Overall, 88 of the 368 (23.9%) patients had a thyroidectomy of which 30 (34.1%) were neoplastic and 23 (26.1%) malignant. The neoplastic rate for patients who were once diagnosed with AUS/FLUS was 8.2% and the malignancy rate 6.3%. The malignancy rate for patients on follow‐up at the time we prepared the study was 15.7% (23/146); 222 remained on follow‐up without surgery or repeat FNA or were managed elsewhere. Conclusions: Although in this category repeat FNA is expected rather than excision, we suggest evaluation of all AUS/FLUS patients in multidisciplinary meetings to decide management and recommend follow‐up of all patients with this diagnosis.     

Diagnosis of icteric-type hepatocellular carcinoma by fine needle aspiration: a case report

BACKGROUND: Bile duct invasion is very rare in patients with hepatocellular carcinoma (HCC). It usually presents difficult problems with the clinical differential diagnosis. Moreover, another difficulty might arise when an obstructive jaundice patient is found to have past history of 2 separate malignancies. Fine needle aspiration (FNA) becomes the method of choice for clarification of the bile duct tumor thrombus. CASE: A 72-year-old man presented with progressive obstructive jaundice for 1 month. Past history revealed the occurrence of 2 distinct malignancies during the previous 3 years; they had been resected successfully. Initial imaging studies, including abdominal sonography and computed tomography, were negative for the liver. However, FNA demonstrated clusters of pleomorphic and hyperchromatic cancer cells with an increased nuclear/cytoplasmic ratio proliferating in a vague trabecular pattern with some appearance of sinusoids. Multinucleated giant cells were seen. No bile duct epithelial cells were seen. The diagnosis of the third separate malignancy, moderately differentiated HCC, was made. CONCLUSION: To our knowledge, this is the first report of icteric-type HCC diagnosed by FNA although the primary lesion was undetectable on routine, noninvasive examinations. FNA cytology is an accurate and minimally invasive method for early confirmation of biliary HCC thrombi.     

Fine needle aspiration of the thyroid. Distinction between colloid nodules and follicular neoplasms using cell blocks and 21-gauge needles

Although fine needle aspiration (FNA) of the thyroid has been found to be useful in selecting patients for surgery in most cases, the cytologic differentiation of cellular colloid nodules from follicular neoplasms has not been possible because of the scanty amount of tissue obtained by this technique and because of the infrequent preparation of cell blocks, thus precluding appreciation of the tissue architecture. Review of the histology of nodular goiters and follicular neoplasms and comparison of their morphology in smears and cell blocks from FNA specimens with the histology of the surgically excised specimens in 74 cases revealed the presence of hyperplastic papillae and fragments of dilated follicles in the aspirates of most cases of colloid nodules. These two features appear to be specific for colloid nodules and are useful for distinguishing colloid nodules from follicular neoplasms. The merits of using a 21-gauge needle and of preparing cell blocks in thyroid studies are also discussed.     

甲状腺良、恶性结节的临床、超声及细胞学特征分析

目的:研究良、恶性甲状腺结节的相关临床因素、超声特征与甲状腺细针穿刺细胞学检查结果之间的关系。方法:收集2010年1月至2013年12月在上海市第一人民医院因甲状腺结节就诊,并进行超声引导下FNAB检查患者的临床资料,以FNAB细胞学诊断结果为诊断标准,分析和比较不同性质甲状腺结节患者的年龄、性别、甲状腺疾病家族史、临床症状、血清甲状腺激素、甲状腺自身抗体(TPOAb和TRAb)水平,超声检查所发现的结节数量、性状、前后径与横径比(AP/TR)、回声类型、钙化类型、边界状态、血流情况等因素,采用Logistic多因素回归,探讨这些临床和超声特征与甲状腺良、恶性结节之间的关系。结果:根据FNAB结果,1592例患者中,良性结节者1492例,恶性结节者77例,结果不确定者23例。以良性组作为对照,年龄40岁、TPOAb(+)是恶性甲状腺结节的独立危险因素(P0.05);出现钙化点、细小钙化斑、边界不规整的超声表现的恶性甲状腺的风险显著升高(P0.05)。结论:超声检查甲状腺结节出现钙化点、细小钙化斑或边界不规整等与FNAB诊断的甲状腺恶性结节之间存在明显的关联。     

Oncocytic nodule. An unusual case of a submaxillary gland mass in an elderly patient

A submaxillary gland mass in an elderly woman was diagnosed as an oncocytic nodule by cutting needle biopsy and was followed with serial fine needle aspiration (FNA) biopsy for seven years. All specimens showed pure populations of oncocytes. Oncocytic nodules of the salivary gland are unusual lesions that may represent hyperplastic proliferations or true neoplasms. Although oncocytic metaplasia is commonly identified in the salivary glands of elderly patients, oncocytes rarely form masses that are targets for needle biopsy. This case suggests that FNA biopsy may be a useful method of evaluating salivary gland lesions in elderly patients who are not candidates for surgery.     

Detection of medullary thyroid microcarcinoma using ultrasound‐guided fine needle aspiration cytology

G. C. H. Yang, K. Fried and P. H. Levine Detection of medullary thyroid microcarcinoma using ultrasound‐guided fine needle aspiration cytology Objective: Compared with incidental papillary thyroid microcarcinoma (microPTC), incidental medullary thyroid microcarcinoma (microMTC) is clinically more significant. The objective of the present study was to summarize our experience in detecting microMTCs. Methods: From 1995 to 2011, there were 10 825 thyroid fine needle aspirates (FNAs) guided using high‐resolution ultrasound with on‐site preparation and evaluation by a cytopathologist. Of the 140 microcarcinomas detected, 132 were microPTCs and eight were microMTCs, which are the subject of the present study. Results: All eight cases were incidentalomas and none of the five women and three men, age 37–70 years, had a family history of MTC. One patient had two FNAs at an interval of 10 months, two had a single lymph node metastasis and one had a 0.1‐cm tumour nodule near the main tumour. Four of five plasmacytoid cell microMCTs had irregular borders; two round cell and one rectangular cell tumours had smooth borders. In contrast, 17 larger MTCs diagnosed in the same period included seven plasmacytoid, four giant cell and six spindle cell types. All five plasmacytoid microMTCs were correctly diagnosed on FNA, but the round cell and rectangular cell tumours were undercalled as follicular lesions. Sampling of colloid from adjacent follicles was noted in microMTCs. Two were diagnosed on histology following recommended surgery and one was diagnosed on recommended repeat FNA. Conclusions: US‐guided FNA of thyroid lesions is a powerful tool in the detection of microMTCs, provided that cytopathologists are alerted to the pitfalls described in the present study.     

Thyroid fine needle aspiration cytology: a review of the National Cancer Institute state of the science symposium

L. J. Layfield, E. S. Cibas and Z. Baloch
Thyroid fine needle aspiration cytology: a review of the national cancer institute state of the science symposium In October 2007, the National Cancer Institute (NCI) of the United States sponsored a conference reviewing the state of the science of thyroid fine needle aspiration (FNA). Multiple issues were reviewed including pre‐FNA requirements, training specifications, criteria for the selection of patients to undergo FNA, diagnostic categories and criteria, ancillary testing and post‐FNA follow‐up and treatment options. A summation of conclusions covering three of these topics, followed by a question and answer session, was subsequently presented at the 35th European Congress of Cytology (ECC) in Lisbon, Portugal in September of 2009. At the ECC, the findings of the NCI committee proposals regarding the indications for FNA of thyroid nodules, diagnostic categories and criteria, and post‐FNA options for follow‐up and treatment were discussed. Herein we review the presentations given at that conference.     

Immunohistochemical assessment of proliferating cell nuclear antigen in primary hepatocellular carcinoma and dysplastic nodules

A complementary way for the assessment of HCC prognosis is represented by the analysis of molecular markers. Thus, immunohistochemical assessment of proliferation can describe tumor aggressiveness, probability of local recurrence or metastasis potential, being very useful for the assessment of recurrence-free survival and survival until death. The aim of our study was to assess proliferating cell nuclear antigen activity in HCC and dysplastic nodules as compared with surrounding nonneoplasic areas. Immunohistochemical techniques were thus performed on the samples obtained by ultrasound-guided liver biopsies or intraoperative biopsies, in 32 patients with HCC, as well as in 3 patients with dysplastic nodules ocurring in liver cirrhosis. Expression of PCNA within extranodular areas of the HCC patients in the absence or presence of cirrhosis, was increasing from 40% to 70%, respectively. PCNA expression further increased within intranodular areas of dysplastic nodules and HCC, to 100% and 96.88%, respectively. A progressive increase of the mean values of PCNA-LI was also observed from extranodular areas without or with cirrhosis, towards intranodular areas of dysplastic nodules and HCC (4.2%, 6.8%, 31.9%, respectively). Dysplastic nodules can thus be considered lesions with a high-proliferation rate, representing an early stage of hepatocarcinogenesis. This supported the current recommendations for borderline hepatocellular nodules identified by ultrasound, which indicate an aggressive treatment similar to malignant lesions. In summary, we demonstrated a progressively increasing rate of cellular proliferation, from extranodular non-neoplasic areas to intranodular areas (dysplastic nodules and HCC), as reflected by an increased expression of proliferating cell nuclear antigen labelling index.     

Fine needle aspiration cytologic study of the solitary thyroid nodule. Profile of 308 cases with histologic correlation

The cytologic features and diagnoses of 308 solitary thyroid nodules subjected to fine needle aspiration (FNA) are presented and correlated with the histopathology. The findings reconfirmed the overall utility of FNA cytology in the differentiation of benign from neoplastic lesions and in the specific diagnosis of most types of thyroid lesions. The difficulty in the diagnosis of follicular carcinoma and in its differentiation from follicular adenoma is highlighted. Of note was the finding of Hürthle-cell populations in several types of lesions, which represents a potential diagnostic problem; this potential difficulty was lessened by sampling two or three areas within a nodule, thus obtaining a more truly representative specimen.     

Effect of ultrasound transmission gel on ultrasound‐guided fine needle aspiration cytological specimens of thyroid

A. Lalzad, D. Ristitsch, W. Downey, A. F. Little and M. E. Schneider‐Kolsky
Effect of ultrasound transmission gel on ultrasound‐guided fine needle aspiration cytological specimens of thyroid Objective: To investigate prospectively the diagnostic impact of ultrasound coupling gel on thyroid specimens obtained under ultrasound guidance. Methods: Patients presenting for ultrasound‐guided fine needle aspiration (USG‐FNA) of the thyroid were invited to participate in the study. Four specimens per nodule were collected: two using chlorhexdine wash and two using sterile, colourless ultrasound gel as couplant according to routine protocol. All slides were analysed in a blinded fashion by two senior cytologists for the presence or absence of ultrasound gel‐induced artefacts. The presence of gel‐induced artefacts between the two groups was analyzed using Pearson’s chi‐square test. Kappa statistics were used to measure the inter‐rater agreement between the cytologists. Results: Twenty thyroid nodules comprising 80 specimen slides were collected. On slides collected with gel, cytological artefacts were detected in 60–65% of cases compared with 10–15% of cases without gel (P < 0.001). The inter‐rater agreement between the two observers was very good (κ = 0.84). Two of the 14 patients required repeat FNA due to non‐diagnostic cytology results caused by inadequate sampling and gel‐induced artefacts. Conclusions: Clinical cytopathologists, radiologists and sonographers should be aware of the potential for ultrasound gel to cause significant artefacts on cytological specimens. Our findings suggest that staff involved in USG‐FNA cytology should remove the gel carefully before taking the aspirate.     

Diagnostic pitfalls in the fine needle aspiration of thyroid nodules. A study of 555 cases in Chinese patients

The diagnostic value and limitations of fine needle aspiration (FNA) were determined by examining 555 palpable thyroid nodules in Chinese patients who had a definitive diagnosis established by thyroidectomy (529 cases) or large-needle biopsy (26 cases). Of the aspirates, 97.8% were satisfactory for cytologic examination. The overall malignancy rate was 20%. FNA detected 73 (74.5%) of 98 primary malignant tumors and 9 (90%) of 10 metastatic tumors. Diagnostic errors were most commonly due to inadequate specimens and cystic lesions. Cystic fluid, present in one-third of all lesions, was associated with a malignant nodule in 13% of the cases. FNA was most valuable for detecting papillary carcinomas; it may at times suggest the likelihood of a follicular carcinoma.