Management of thyroid cytological material,preanalytical procedures and bio‐banking

Thyroid nodules are common and are increasingly detected due to recent advances in imaging techniques. However, clinically relevant thyroid cancer is rare and the mortality from aggressive thyroid cancer remains constant. Fine needle aspiration cytology (FNAC) is a standard method for diagnosing thyroid malignancy and the discrimination of malignant nodules from goitre. As the examined nodules on thyroid FNAC are often small incidental findings, it is important to maintain a low rate of undetermined diagnoses requiring further clinical work up or surgery. The most important factors determining the accuracy of the cytological diagnosis and suitability for biobanking of thyroid FNACs are the quality of the sample and availability of adequate tissue for auxiliary studies. This article discusses technical aspects (preanalytics) of performing thyroid FNAC, including image guidance and rapid on‐site evaluation, sample collection methods (conventional slides, liquid‐based methods, cell blocks) and storage (bio‐banking). The spectrum of special studies (immunocytochemistry on direct slides or liquid‐based cytology, immunohistochemistry on cell blocks and molecular methods) required for improving the precision of the cytological diagnosis of the thyroid nodules is also discussed.     

Dipeptidyl peptidase IV expression in thyroid cytology: retrospective histologically confirmed study

Fine needle aspiration cytology (FNAC) of the thyroid gland is a well-established method. However, it has inherent limitations, especially in the diagnosis of follicular and oncocytic tumours and in distinguishing between nuclear atypia in colloid goitre with regressive changes and cystic papillary carcinoma. The aim of our study was to evaluate dipeptidyl peptidase IV (DPP IV) as a marker of malignancy in FNAC. We tested 254 thyroid specimens (intraoperative imprint smears) for DPP IV. The sensitivity was 71%, the specificity was 96%, and the diagnostic accuracy was 93%, respectively, with a threshold of 50% of positive cells. To the best of our knowledge it is the largest histologically confirmed study reported in the literature. We suggest the assessment of DPP IV as an adjunct diagnostic marker of malignancy in thyroid specimens suspicious of papillary carcinoma. However, the value of the marker in follicular lesions is very limited.     

Cytology and mRNA expression analysis of fine needle aspirates of thyroid nodules in an East German region with borderline iodine deficiency.

Fine needle aspiration cytology (FNAC) is widely recommended as an important tool for pre-operative identification of malignancy in patients with nodular thyroid disease. To assess the diagnostic contribution of FNAC and the potential of quantitative mRNA analysis in fine needle aspirates in daily practice, we conducted a prospective study in thyroid clinics (n=2) and endocrine practices (n=3), respectively in an East German region with borderline iodine deficiency. Two-hundred and forty-four consecutive FNACs were obtained over a period of 2 years (2002-2004) from euthyroid patients presenting for first evaluation of a solitary thyroid nodule. The mean nodule size for FNAC was 27 mm (range: 10-79 mm). In 55% of patients FNAC was performed after scintiscan detection of a cold or normal functioning thyroid nodule (CTN), while in the remainder FNAC was performed as a primary investigation. FNAC outcomes were: 57.8% benign, 22.1% indeterminate, 2.5% suspicious for malignancy, 17.6% non-diagnostic. Messenger RNA levels for a house keeping gene (beta-actin) and a thyroid specific marker (thyroglobulin, Tg) were studied as basic molecular markers using real-time PCR. Both in the IN VIVO and EX VIVO FNA series, beta-actin and Tg mRNA levels were positively correlated with the thyrocyte cell yield/respective FNA smear. However, subgroup analysis showed that FNAC with histologically confirmed follicular thyroid cancer and/or microfollicular adenoma exhibited significantly lower Tg mRNA expression despite high beta-actin levels. Sufficient mRNA quantities were obtained in >90% of FNA specimen to allow quantitative mRNA analysis of at least 5 further genes. In conclusion, quantitative mRNA analysis is feasible in FNA on a routine basis and provides a perspective for a molecular distinction of thyroid nodules, once specific marker genes have been defined for benign and malignant thyroid tumours respectively.     

Same-Day Fine-Needle Aspiration Cytology Diagnosis for Thyroid Nodules Achieves Rapid Anxiety Decrease and High Diagnostic Accuracy

Objective: The time between the moment of referral for the diagnostic workup for thyroid nodules and the outcome can be worrisome for patients. In general, patients experience high levels of anxiety during the evaluation of a lesion suspicious for cancer. Therefore, the implementation of same-day fine-needle aspiration cytology (FNAC) diagnosis is becoming standard-of-care for many solid tumors. Our aim was to assess the feasibility of same-day FNAC diagnosis for thyroid nodules and to assess patient anxiety during the diagnostic process.Methods: For feasibility of same-day FNAC diagnosis, we assessed the proportion of patients receiving a diagnosis at the end of the visit. Accuracy was measured by comparing histology with the FNAC result. Patient anxiety was measured by the State Trait Anxiety Inventory at 6 moments during the diagnostic workup.Results: Of the 131 included patients, 112 (86%) were female, and the mean age was 53 years. All patients, except those with a nondiagnostic FNAC result (n = 26; 20%), had a diagnosis at the end of the day. There were only two discordant results. Anxiety levels at the beginning of the day were high throughout the group, State Trait Anxiety Inventory (STAI) score 43.1 (SD 2.0) and decreased significantly more in patients with a benign FNAC result (STAI score 30.2), compared to patients with a malignant or indeterminate result (STAI score 39.6).Conclusion: Distress of patients with a thyroid nodule undergoing same-day FNAC diagnostics was high. Same-day FNAC diagnosis is feasible and accurate for the evaluation of thyroid nodules. Therefore, same-day FNAC diagnosis seems a safer, more patient-friendly approach to diagnose thyroid nodules.Abbreviations:AUS = atypia of undetermined significanceCWS = Cancer Worry ScaleFNAC = fine-needle aspiration cytologySTAI = State Trait Anxiety InventoryTSH = thyroid-stimulating hormone     

Initial axillary staging of breast cancer using ultrasound‐guided fine needle aspiration: a liquid‐based cytology study

A. Schiettecatte, C. Bourgain, C. Breucq, N. Buls, V. De Wilde and J. de Mey
Initial axillary staging of breast cancer using ultrasound‐guided fine needle aspiration: a liquid‐based cytology study Objective: To evaluate the preoperative detection of axillary metastasis combining ultrasound (US)‐guided fine needle aspiration cytology (FNAC) and liquid‐based cytology (Surepath^®) to reduce sentinel node procedures. Methods: In total, 148 patients with clinically negative lymph nodes and no preoperative therapy were included. All patients underwent preoperative ultrasound of the axilla with FNAC if suspicious lymph nodes were found. Complete axillary lymph node dissection was performed at primary surgery when FNAC was positive. All other patients underwent a sentinel node procedure. Results: US‐guided FNAC of the axilla revealed metastasis in 34 (23.0%) of the 148 patients. These 34 patients were 53.1% of all patients (n = 64) with proven axillary lymph node involvement. In 66 patients (44.6%), both ultrasound and histopathology were negative. Overall sensitivity of US‐guided FNAC was 50.0%, specificity 100%, positive predictive value 100% and negative predictive value 70.2%. In T1 tumours, all patients referred for sentinel node procedure were node‐negative. The correlation between malignant FNAC and histopathology was 100%. US‐guided liquid‐based FNAC in patients with no clinically positive lymph nodes reduced the necessity for a sentinel node procedure by 23.0%. Conclusions: We advocate that US‐guided fine needle aspiration (FNA) combined with liquid‐based cytology of axillary lymph nodes should be included in the preoperative staging of breast cancer.     

Fine needle aspiration cytology of Langerhans cell histiocytosis of the thyroid. A case report.

BACKGROUND: Langerhans cell histiocytosis (LCH) of the thyroid is a rare condition, and fine needle aspiration cytology (FNAC) of this entity has rarely been described. CASE: FNAC was done on a 3-cm-diameter thyroid swelling in the left lower lobe of the thyroid gland. Smears showed a large number of lymphocytes, eosinophils, thyroid follicular cells and discrete, large cells with prominent nuclear grooves. Mitotic activity was frequent. A cytologic diagnosis of LCH was offered. Subtotal thyroidectomy was performed, and the cytologic diagnosis was confirmed by histology. CONCLUSION: LCH of the thyroid has certain salient diagnostic features. The presence of histiocytes with prominent nuclear grooves, reactive lymphoid cells and eosinophils along with benign thyroid follicular cells should raise the suspicion of this rare entity on FNAC smears of the thyroid.     

Occult medullary carcinoma of thyroid with lymph node metastases: a case report

BACKGROUND: Occult thyroid malignancies presenting with secondary neck masses as the first clinical manifestation is well known. Although rare, medullary carcinoma serves a potential source for lymph node metastases. The characteristic cytomorphology of medullary thyroid carcinoma (MTC) should clinch the diagnosis. Further, fine needle aspiration cytology (FNAC) of the ultrasonography-detected occult nodules in thyroid serves as a useful preoperative diagnostic tool. CASE: A 22-year-old man presented with left-sided neck masses of 1 year duration. FNAC smears of the neck masses revealed cytomorphology characteristic of MTC. Ultrasonography of the thyroid led to ruling out the presence of an occult nodule and detected an 8-mm nodule in the left thyroid lobe. Ultrasound-guided FNAC of the nodule showed features similar to those with FNAC of the neck masses. Surgical resection of thyroid and neck masses further confirmed the diagnosis of a primary occult MTC with lymph node metastases. CONCLUSION: FNAC smears of lymph node masses showing the distinct cytomorphology of MTC should prompt suspicion for occult primary in thyroid. Ultrasound-guided FNAC of these occult nodules, if detected, further serves a diagnostic tool for accurate preoperative diagnosis when metastasis presents as the first clinical manifestation of an occult primary.     

Posters. P1 A 2‐year audit of thyroid fine needle aspiration cytology

Introduction Fine needle aspiration (FNA) cytology of the thyroid is a well‐established test in the clinical work‐up of patients with solitary nodules of the thyroid. Thyroid FNA does however have limitations and audit of diagnostic performance is important. Methods The histopathology archives of the Royal Victoria Hospital were searched for all thyroid resections and the histopathological diagnosis was correlated with the pre‐operative cytological diagnosis, where available. Special emphasis was placed on the accuracy of tumour diagnosis. Results A total of 173 cases were identified during the 2‐year period, of these 93 had available pre‐operative FNA. A total of 57 tumours were identified. A small number (six of 57) of significant discrepancies were identified. These included a malignant lymphoma diagnosed as Hashimoto's thyroiditis, a metastasis which the FNA had suggested was a medullary carcinoma and an insular carcinoma diagnosed as medullary carcinoma on FNA. False positives included a colloid cyst diagnosed as suspicious of malignancy and a cytological diagnosis of papillary carcinoma not confirmed on histology. Discussion At present, the majority of thyroid FNAs in our clinics are performed by surgeons and material is not routinely available for immunocytochemistry. In spite of these limitations, there were few major discrepancies. These might be reduced if pathologist aspirators were able to perform FNAs and collect material for further studies, where necessary. This would allow identification of medullary carcinomas and malignant lymphomas. Conclusion FNA of thyroid lesions is a useful investigation in our clinical setting, however, some areas of potential for improvement have been identified.     

Fine needle aspiration cytology and immunocytochemistry in tuberculous thyroiditis: a case report

BACKGROUND: Tuberculosis of the thyroid is very rare and does not strike the clinician as a first clinical diagnosis of a thyroid nodule. To our knowledge, only 40 cases of tuberculous thyroiditis diagnosed by fine needle aspiration cytology (FNAC) are described in the English literature. CASE: We report a case of tuberculous thyroiditis in a young woman who presented with a right-side solitary thyroid nodule of short duration (15 days), diagnosed by FNAC and confirmed by positive immunocytochemistry with monoclonal antibody to Mycobacterium tuberculosis complex. Ziehl Neelsen staining for acid-fast bacilli (AFB) was negative. CONCLUSION: FNAC provides a confident preoperative diagnosis of thyroid tuberculosis, obviating the need for unnecessary surgical removal of thyroid nodule. Immunocytochemistry is an important diagnostic adjunct to FNAC in AFB-negative cases.     

Ectopic lesions as potential pitfalls in fine needle aspiration cytology: a report of 3 cases derived from the thyroid, endometrium and breast

BACKGROUND: Ectopic lesions are rarely encountered. Those that are derived from thyroid, breast, endometrium and salivary glands present with palpable masses that can mimic malignancy. Fine needle aspiration cytology (FNAC) is a practical procedure for the differential diagnosis of such lesions but can reveal surprising images for a cytopathologist. CASES: Three cases of discrete, ectopic lesions at different locations occurred. Case 1 was a 27-year-old woman. Upon diagnosis of a submandibular mass with a diameter of 1 cm, FNAC was performed. The smears showed crowded thyroid follicular cells comprising papillary clusters. A cytologic diagnosis of papillary thyroid lesion was rendered, Histopathology revealed that this lesion was ectopic thyroid tissue with focal chronic thyroiditis. Case 2 was a 38-year-old woman who presented with a painful mass with a diameter of 2.5 cm in the abdominal wall. The patient had undergone cesarean section 3 years earlier. The case was diagnosed on FNAC as low grade malignancy in which an adenocarcinoma/mesenchymal tumor distinction could not be made. The pathologic examination revealed endometriosis. Case 3 was a 31-year old woman who presented with a palpable nodule in the axillary region with a diameter of 1 cm. The patient had given birth 1 month earlier and was nursing. An FNAC diagnosis of lactation ectopic breast tissue was made. The mass disappeared by the end of lactation. CONCLUSION: FNAC of ectopic lesions may prove to be a diagnostic pitfall for cytopathologists. A cytopathologist who encounters a cellularpicturefrom a lesion that is outside the normal anatomic location must use a cautious diagnostic approach. Unless there are clear findings, the cytopathologist must refrain from a diagnosis of malignancy.     

Thyroid tuberculosis – role of PCR in diagnosis of a rare entity

N. Gupta, K. Sharma, A. Barwad, M. Sharma, A. Rajwanshi, P. Dutta and A. Sharma
Thyroid tuberculosis – role of PCR in diagnosis of a rare entity Background: Tuberculosis is a rare cause of granulomatous thyroiditis, whose diagnosis may be difficult with routine cytopathology and staining for acid‐fast bacilli (AFB). Study design: Amongst 7962 cases of various thyroid lesions subjected to fine needle aspiration cytology (FNAC) over a period of 12 years, 34 cases (0.43%) were found to have cytological features of granulomatous inflammation with or without necrosis, which could be due to tuberculosis, granulomatous thyroiditis or other causes of granulomatous inflammation such as sarcoidosis or fungal infections. DNA was extracted from the material available on May‐Grünwald–Giemsa‐stained smears from the archival material. PCR for Mycobacterium tuberculosis was performed for insertion sequence IS6110. Results: The age of the patients ranged from 32 to 58 years (median 48 years); 24 were female and 10 male. FNAC from thyroid swellings showed epithelioid granulomas with giant cells and/or necrosis. Although acid‐fast bacilli were only seen in smears in two cases, 19/34 (55.9%) showed the presence of 123 bp DNA band under ultraviolet transillumination. Five control cases were negative. Conclusion: Our study of archival cytological material illustrates the importance of PCR as a potentially useful tool for the detection of M. tuberculosis DNA from FNAC of thyroid lesions, which could provide an alternative for rapid diagnosis of thyroid tuberculosis in AFB‐negative cases.     

Fine needle aspiration cytology of thyroid nodules: how accurate is it and what are the causes of discrepant cases?

Fine-needle aspiration cytology (FNAC) is widely accepted as the most accurate, sensitive, specific and cost-effective diagnostic procedure in the assessment of thyroid nodules and helps to select people preoperatively for surgery. The purpose of this study was to evaluate the results of thyroid FNAC in our institution and to determine the reasons for discrepancies between the cytological and histological diagnosis. We evaluated the cytological and histological results of 254 FNACs obtained from 231 patients who underwent subsequent thyroid surgery. All of the material was blindly reviewed for quality control, by one experienced cytopathologist. All FNACs were carried out under ultrasound guidance. The cytological diagnosis was classified as benign, suspicious, malignant or unsatisfactory. The definitive histological study showed benign lesions in 195 of the 231 patients (84%). A benign diagnosis based on FNAC was correct in 105 of the 108 benign cases (97%). FNACs diagnosed as 'suspicious' resulted in a distribution of 49 benign (79%) and 13 malignant (21%) diagnoses. FNAC showed malignancy in 34 cases (13%) and in only one case did the final histology differ from cytology (correlation 97%). The percentage of FNACs that were inadequate for diagnosis was 20%. Review of cytological and histological slides did not lead to any change in the original diagnosis. Our study revealed a cytological-histological discrepancy (2%) in only 4 out of 231 cases over a period of 10 years, due to either a diagnostic or sampling error.     

Malignancy Risk Analysis in Patients with Inadequate Fine Needle Aspiration Cytology (FNAC) of the Thyroid

Background

Thyroid fine needle aspiration cytology (FNAC) is the standard diagnostic modality for thyroid nodules. However, it has limitations among which is the incidence of non-diagnostic results (Thy1). Management of cases with repeatedly non-diagnostic FNAC ranges from simple observation to surgical intervention. We aim to evaluate the incidence of malignancy in non-diagnostic FNAC, and the success rate of repeated FNAC. We also aim to evaluate risk factors for malignancy in patients with non-diagnostic FNAC.

Materials and Methods

Retrospective analyses of consecutive cases with thyroid non diagnostic FNAC results were included.

Results

Out of total 1657 thyroid FNAC done during the study period, there were 264 (15.9%) non-diagnostic FNAC on the first attempt. On repeating those, the rate of a non-diagnostic result on second FNAC was 61.8% and on third FNAC was 47.2%. The overall malignancy rate in Thy1 FNAC was 4.5% (42% papillary, 42% follicular and 8% anaplastic), and the yield of malignancy decreased considerably with successive non-diagnostic FNAC. Ultrasound guidance by an experienced head neck radiologist produced the lowest non-diagnostic rate (38%) on repetition compared to US guidance by a generalist radiologist (65%) and by non US guidance (90%).

Conclusions

There is a low risk of malignancy in patients with a non-diagnostic FNAC result, commensurate to the risk of any nodule. The yield of malignancy decreased considerably with successive non-diagnostic FNAC.     

Follicular variant of papillary thyroid carcinoma: diagnostic limitations of fine needle aspiration cytology

OBJECTIVE: To study the diagnostic sensitivity and specificity of fine needle aspiration cytology (FNAC) offollicular variant of papillary thyroid carcinoma (FVPTC). STUDY DESIGN: The study group consisted of 390 papillary thyroid carcinoma (PTC) cases diagnosed histologically with thyroidectomy specimens. The FNAC and histopathologic classification were compared in terms of the appearance of FVPTC and non-FVPTC statistically with the chi squared test. Also, several features of the cytologic smears of FVPTC were reviewed. RESULTS: Twelve of the 390 PTC cases were classified as FVPTC histologically. Five of the 12 cases were also reported as FVPTC in the diagnosis by FNAC and the other 7 as the usual type of PTC (UTPTC). There was 1 case classified as UVPTC histologically but FVPTC cytologically. If we use histologic diagnosis as the gold standard, the sensitivity and specificity of FNAC diagnosis of FVPTC were 42% and 83%, respectively. CONCLUSION: FNAC may be a good tool for diagnosing PTC, but it is unreliable to differentiate between FVPTC and UTPTC.     

Contribution of the neural cell recognition molecule NB‐3 to synapse formation between parallel fibers and Purkinje cells in mouse

The neural cell recognition molecule NB‐3, also referred to as contactin‐6, is expressed prominently in the developing nervous system after birth and its deficiency has been shown to cause impairment in motor coordination. Here, we investigated the contribution of NB‐3 to cerebellar development, focusing on lobule 3 where NB‐3 was expressed in granule cells but not in Purkinje cells. In the developing molecular layer, the neural cell recognition molecules TAG‐1, L1, and NB‐3 formed distinct expression zones from the external granule cell layer to the internal granule cell layer (IGL), respectively. The NB‐3‐immunoreactive zone did not overlap with TAG‐1‐immunoreactive zone. By contrast, the L1‐immunoreactive zone overlapped with both the TAG‐1‐ and NB‐3‐immunoreactive zones. NB‐3‐positive puncta overlapped with vesicular glutamate transporter 1, a presynaptic marker and were apposed close to metabotropic glutamate receptor 1A, a postsynaptic marker, indicating that NB‐3 is localized presynaptically at glutamatergic synapses between parallel fibers and Purkinje cells. In NB‐3 knockout mice, L1 immunoreactive signals were increased in the IGL at postnatal day (P) 5, suggesting the increase in the number of immature granule cells of the IGL. In addition, the density of parallel fiber synaptic terminals was reduced in NB‐3 knockout mice relative to wild‐type mice at P5 to P10. In parallel with these findings, caspase‐dependent cell death was significantly increased in the NB‐ 3‐deficient cerebellum at P15. Collectively, our results indicate that NB‐3 deficiency affects synapse formation during postnatal cerebellar development. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009     

Value of repeated fine needle aspiration cytology in patients with nodular goiter

OBJECTIVE: To assess the value of reaspiration cytology in benign nodular thyroid disease. DESIGN: We prospectively studied 400 patients (365 women, 35 men) aged 46 years (18-89) with nodular thyroid disease and initial benign fine needle aspiration cytology (FNAC). Reaspiration of the same nodule was performed in a median follow-up time of 14 months (6-18). RESULTS: Repeat FNAC was benign in 346 patients (86.5%), insufficient for diagnosis in 42 (10.5%), suspicious in 16 (2.5%) and malignant in 2 (0.5%). All diagnostic changes to suspicious malignant cytology took place in patients with solitary nodules. Surgery confirmed thyroid cancer in the 2 patients with malignant cytology, in 5 of 10 patients with suspicious cytology and in none of 39 patients with benign cytology who underwent surgery for other reasons. Clinical changes (size increase or local symptoms) were not related to changes in cytologic diagnosis after a second aspiration, nor with the results of the biopsy. CONCLUSION: Repeat aspiration cytology of thyroid nodules may correct initial false negative results because of cytologic misdiagnosis, occurring in 1.75% of patients, whereas clinical changes did not contribute to diagnosis change. Repeat aspiration cytology is recommended in all patients with nodular goiter.     

Ultrasound-guided fine needle aspiration cytology in the diagnosis and management of thyroid nodules

OBJECTIVE: To examine the accuracy of fine needle aspiration cytology (FNAC) in the diagnosis of thyroid nodules and compare the inadequacy rates for ultrasound-guided and freehand FNAC. METHODS: A retrospective study of 434 patients with thyroid nodules who underwent diagnostic FNAC over a 2-year period. Cytological diagnoses have been compared with the histological assessment of resection specimens in 69 cases. RESULTS: The inadequacy rate was significantly lower from ultrasound guided FNAC (24/373 cases, 6.4%) than from freehand FNAC (8/61 cases, 13.1%) (P = 0.043). Seventy-six percentage of patients had a non-neoplastic cytological diagnosis and, after multidisciplinary review, the patients were reassured and assigned to clinical follow-up. Sixty-seven patients had a resection for cytological appearances consistent with non-neoplastic disease (n = 34), suspicious of follicular neoplasia (n = 23), or suspicious of malignancy (n = 10), and two patients had resections following inadequate cytology with ultrasound appearances suspicious of a neoplasm. The overall accuracy of FNAC analysis for malignancy was 97.0%, with sensitivity 83.3%, specificity 98.0%, positive predictive value 71.4% and negative predictive value 98.4%. The overall accuracy of FNAC analysis for the prediction of neoplasia was 97.5%, with sensitivity 80.5%, specificity 97.8%, positive predictive value 89.2% and negative predictive value 95.9%. Difficulties in cytological diagnosis were associated with lymphoid infiltrates and with degenerative changes in follicular adenomas. CONCLUSION: Ultrasound-guided FNAC has a significantly lower yield of inadequate aspirates than palpable FNAC. The ability of FNAC to predict neoplasia in 89% patients and to exclude neoplasia in 95.9% patients makes an important contribution to the multidisciplinary assessment of patients.     

Isolated carcinoid tumor metastatic to the thyroid gland: report of a case initially diagnosed by fine needle aspiration cytology

BACKGROUND: Neuroendocrine tumor metastatic to the thyroid gland is rare and may be difficult to differentiate from primary thyroid neuroendocrine tumors, such as medullary thyroid carcinoma (M/ITC). This report describes an unusual case of bronchial carcinoid metastatic to the thyroid diagnosed by fine needle aspiration cytology (FNAC). CASE: A 42-year-old woman with an undiagnosed bronchial carcinoid tumor presented to our clinic with a solitary nodule in the thyroid gland. FNAC of the nodule showed loosely cohesive groups of cuboidal tumor cells with scant, slightly granular cytoplasm; centrally located nuclei with a coarsely granular, salt-and-pepper chromatin pattern and inconspicuous nucleoli. Immunocytochemically the tumor cells were positive for neuron-specific enolase, chromogranin and synaptophysin and negative for thyroglobulin, calcitonin and carcinoembryonic antigen. The cytologic diagnosis of a metastatic neuroendocrine carcinoma was confirmed histologically. CONCLUSION: Metastasis to the thyroid gland may pose a diagnostic problem, particularly with tumors of neuroendocrine origin, as these have similar cytologic features in various organs. The correct preoperative cytologic diagnosis of metastatic carcinoid tumor in patients without a prior history of cancer and differential diagnosis with MTC are crucial because prognosis, workup and treatment are different in each.     

Diagnostic pitfalls in the evaluation of fine needle aspiration cytology of the thyroid: correlation with histopathology in 260 cases

Objectives:  Fine needle aspiration cytology (FNAC) of the thyroid is a non-invasive, cost-effective screening procedure that is valuable for distinguishing neoplastic lesions from non-neoplastic nodules. The aim of this study was to determine the diagnostic accuracy of FNACs performed at our institution by correlating FNAC results with histopathological diagnoses.
Methods:  Two hundred and seventy-one aspiration cytology specimens followed by thyroidectomy were included in the study, and the results of 260 adequate FNACs were compared with their histological diagnoses.
Results:  The sensitivity and specificity of thyroid FNAC for detecting neoplasia were 92.6% and 91.6%, respectively. There were 15 (5.7%) false positives and six (2.3%) false negatives.
Conclusions:  The results showed that follicular cells that exhibit some of the features of papillary carcinoma could be observed in a cytology slide of Hashimoto's thyroiditis, leading to a diagnostic pitfall. In addition, cellularity and overlapping cytological criteria in hyperplasia might lead to a false diagnosis.     

Outcomes of endoscopic ultrasound‐guided pancreatic FNAC diagnosis for solid and cystic lesions at Manchester Royal Infirmary based upon the Papanicolaou Society of Cytopathology pancreaticobiliary terminology classification scheme

Objective

To compare endoscopic ultrasound (EUS)‐FNAC diagnosis of pancreatic lesions with patient outcome based upon the Papanicolaou Society of Cytopathology pancreaticobiliary terminology classification scheme diagnostic categories: Panc 1 (non‐diagnostic); Panc 2 (negative for malignancy/neoplasia); Panc 3 (atypical); Panc 4B (neoplastic, benign); Panc 4O (neoplastic, other); Panc 5 (suspicious of malignancy); and Panc 6 (positive/malignant).

Methods

All EUS‐FNA pancreas specimens taken at Manchester Royal Infirmary in 2015 were prospectively classified according to the above scheme at the time of cytology reporting and data recorded prospectively. Subsequently, outcomes based on clinical follow‐up or histopathology diagnosis were compared with the cytology diagnosis.

Results

120 EUS‐FNA pancreas specimens from 111 patients were received, of which 112 (93.3%) specimens had follow‐up data. There were 79 and 41 EUS‐FNA pancreas specimens from solid and cystic lesions, respectively. Based on the cytology diagnosis the specimens were classified as Panc 1 (7.5%), Panc 2 (33.3%), Panc 3 (2.5%), Panc 4B (2.5%), Panc 4O (15.0%), Panc 5 (3.3%) and Panc 6 (35.9%). The performance indicators for diagnosis of malignancy or neoplasia with malignant potential, included sensitivity (95.4%), specificity (100%), positive predictive value (100%), negative predictive value (92.3%), false positive rate (0%) and false negative rate (4.6%).

Conclusions

The Papanicolaou Society of Cytopathology pancreaticobiliary terminology classification scheme is a logical system that can easily be introduced in a diagnostic cytopathology service. This classification scheme acts as an aid to diagnostic reporting, clear communication of significant results including risk of neoplasia/malignancy to clinicians, clinical audit and comparison of results with other centres.