Fine needle aspiration cytology of solitary fibrous tumours of the pleura

OBJECTIVE: To analyse fine needle aspirates from solitary fibrous tumour (SFT) of the pleura and to elucidate the cytological features unique to these tumours and differential diagnostic findings of benign and malignant SFTs. METHODS: Fine needle aspiration (FNA) cytology slides from eight cases of SFT of the pleura, including six benign and two malignant SFTs, were reviewed. The subsequent histological slides were also examined. RESULTS: Cytological diagnoses from six histologically proven cases of benign SFTs were low-grade sarcoma (one), non-small cell carcinoma (one), malignant tumour (1) and benign (three). Two cases of malignant SFTs were cytologically diagnosed as malignancy. The aspirates showed a varying degree of cellularity. Most smears were composed of single, scattered fusiform cells, and irregular loose aggregates of oval to spindle cells intimately admixed with dense collagenous stroma. Two malignant SFTs had a greater number of cells in clusters, and displayed mitotic activity, without significant cytological atypia. CONCLUSIONS: The diagnosis of SFT may be suggested by a combination of cytological and radiological findings. The precise determination of malignancy for SFT, however, is not usually straightforward on the basis of cytological features alone. The findings of highly cellular clusters and mitotic activity in the FNA cytological smear can help differentiate malignant from benign SFTs.     

Fine needle aspiration cytology (FNAC) of mammary granular cell tumour: a report of three cases

This report describes the FNAC findings in three cases of granular cell tumour of the breast. The patients comprised two females aged 59 and 62 years and one male aged 28 years. All patients presented with a breast lump which was clinically and radiologically suspicious of malignancy. FNAs yielded moderately cellular specimens which on cytologic examipation consisted of groups of cells and single cells with small regular nuclei and abundant granular cytoplasm. Bare nuclei were also present but these did not have the characteristic bipolar appearance of myoepithelial cells. In two cases there was a granularity to the background. The aspirates were reported as equivocal or atypical, probably benign, and surgical biopsy was performed. Histological examination showed typical benign granular cell tumours with strong positive staining for S-100 protein. Pathologists should be aware that granular cell tumour may occur in or around the breast and should consider this diagnosis in aspirates containing a population of cells with regular nuclei and abundant granular cytoplasm. The main cytologic differential diagnoses are likely to be apocrine cells and histiocytes. The suspicion of a granular cell tumour should be heightened when these features are present in an aspirate from a clinically and radiologically suspicious mass. These cases highlight the role of the triple approach encompassing clinical, radiological and cytological features in the assessment of a breast lesion.     

Benign phyllodes tumour vs fibroadenoma: FNA cytological differentiation

The differential diagnosis of fibroadenomas vs phyllodes tumours by fine needle aspiration (FNA) cytology is not possible in the majority of cases. The present study aims to look at common and dissimilar features to allow differentiation, if possible. We reviewed the FNA findings of 18 histologically proven phyllodes tumours and 18 fibroadenomas, checking in each case the epithelial features, the stromal features, and any atypia. Using a semi-quantitative score assessed by two observers we were able in most cases to distinguish a phyllodes tumour from a fibroadenoma. The most important criteria were larger stromal fragments, numerous plump stromal bare nuclei, and the higher ratio of stromal bare nuclei to epithelial bare nuclei in phyllodes tumours. In the present study, an original diagnosis of phyllodes tumour was made in 7/18 (38.9%) cases but with our criteria this could be improved to 15/18 (83.3%) cases. Therefore, the presence of specific stromal features in a dimorphic cellular pattern should suggest the correct diagnosis and differentiate its appearance from a cellular fibroadenoma.     

Cytomorphology of hyaline-vascular Castleman''s disease: a diagnostic challenge

OBJECTIVE: Hyaline-vascular Castleman's disease (CD) is difficult to diagnose on fine needle aspiration and may be mistaken to be a lymphoreticular malignancy because of the presence of large cells having nuclei showing atypical features. The cytomorphological findings in three histopathologically documented cases of hyaline-vascular CD were evaluated to a set of cytomorphological criteria which could help in the identification of this condition on aspirate smears. METHODS: The Papanicolaou and Diff-Quik stained smears from three cases of histologically documented hyaline-vascular CD were reviewed by one author. After review the following cytomorphological criteria were suggested to be indicators of the lesion. (i) The presence of large oval to round cells having ill-defined cytoplasmic margins and large nuclei with irregular nuclear outlines having fine or coarse chromatin giving a crumpled tissue paper appearance. (ii) A polymorphous population of lymphoid cells predominantly of small lymphocytes in the background. The smears from these three cases were then mixed with smears from four cases of reactive lymphoid hyperplasia and three cases of Hodgkin's lymphoma. These ten cases were blindly evaluated by two other cytopathologists in order to evaluate the utility of the proposed criteria in identifying CD. RESULTS: The cytomorphological criteria seen in the methodology section were present in all the cases. These features were helpful in distinguishing CD from reactive lymphoid hyperplasias and Hodgkin's Lymphomas in all cases except one case. CONCLUSION: Although hyaline-vascular CD is a difficult diagnostic entity on aspirate material the presence of large histiocytic cells with a crumpled tissue paper appearance of the nuclei in a background of small lymphocytes are useful indicators for suspecting this lesion. However, these findings should be analysed in larger studies to determine if they could in anyway reduce the diagnostic dilemma in cases of CD.     

Diagnostic difficulties in the interpretation of fine needle aspirates of salivary gland lesions: the problem revisited

Diagnostic difficulties in the interpretation of he needle aspirates of salivary gland lesions: the problem revisited
Cases of salivary gland lesions ( n =325), mainly neoplastic but including a small number of non-neoplastic lesions, investigated by fine needle aspiration (FNA) and with histological correlation, are reviewed. The review identified a number of differential diagnostic problems which are discussed in some detail. One false-positive and eight false-negative diagnoses had been made resulting in a 99.5% specificity and a 85.5% sensitivity. If type-specific diagnoses are made only when all defined diagnostic criteria are present and if any uncertainty is clearly conveyed to the clinician, FNA is a safe and accurate tool in the investigation of salivary gland lesions.     

Diagnosis of a peripheral neuroectodermal tumour by fine needle aspiration

One case of malignant peripheral neuroectodermal tumour successfully diagnosed by cytology is presented. Although a Papanicolaou stained smear could not lead to a diagnosis more specific than a malignant small cell tumour, ancillary analytic methods performed on the cytologic material including immunocytochemistry and electron microscopy yielded the correct diagnosis of peripheral neuroectodermal tumour. This case demonstrates that a precise categorization of small round cell tumours may be achieved by cytology as long as some material is kept for immunocytochemical and ultrastructural studies.     

Higher diagnostic accuracy with the ThinPrep method in a simulated intraoperative environment

Objective:  To compare the accuracy of intraoperative fine needle aspiration cytology samples prepared by the ThinPrep method to conventional cytological methods. Specimen adequacy and turn around time (TAT) were also assessed.
Methods:  Fifty consecutive fresh tumours submitted for histological analysis were aspirated and each prepared as follows: (i) direct smear with H&E stain, (ii) direct smear with Pap stain, (iii) ThinPrep slide with H&E stain, and (iv) ThinPrep slide with Pap stain. The slides were randomly distributed to three cytopathologists for interpretation. The quality of the preparation, the diagnosis and the time needed for interpretation were recorded.
Results:  Accuracy was measured as the percentage of absolute agreement between the cytological and the histopathological diagnoses of the lesions. Histologically, there were 43 malignant and six benign lesions and one atypical lipoma. The TAT began when the slides/cytolyte specimens arrived at the lab and ended with the pathologist's diagnosis.
Conclusions:  In terms of accuracy and specimen adequacy, ThinPrep slides with Pap stain is the best procedure. This advantage however is offset by the longer testing time.     

Fine Needle Aspiration Cytology of Myxoid Liposarcoma; A Study of 18 Tumours

The cytological features of 18 myxoid liposarcomas from 12 patients were analysed. the most consistent cytological features were: abundant myxoid matrix, several small tissue fragments with uniform small, round or stellate cells and a network of branching thin-walled capillaries. the presence of univacuolated or multivacuolated lipoblasts was noted frequently, but not in all aspirates. the diagnostic importance of vacuolated lipoblasts and the main problems of differential cytodiagnosis are discussed. Une série de 18 cytoponctions provenant de 12 patients chez qui un diagnostic de liposarcome myxoïde a été porté cytologiquement et histologiquement est analysée. Les caractéristiques cytologiques les plus constantes sont la présence d'une matrice myxoïde abondante, de petits fragments tissulaires constitués de cellules rondes ou étoilées assez monomorphes et d'un réseau branché de capillaires à paroi fine. La présence de lipoblastes mono ou pluri-vacuolisés est fréquente mais non constante. L'importance diagnostique de ces lipoblastes vacuolisés et les problèmes majeurs de cytodiagnostic différentiel sont discutés. Feinnadelpunktate wurden von 18 histologisch gesicherten myxoiden Liposarkomen von 12 Patienten hergestellt. Die zuverlässigsten zytologischen Kriterien waren: reichlich myxoide Grundsubstanz, kleinere Gewebsfragemente einheitlicher, runder oder sternförmiger Zellen und Bruchstücke dünnwandiger Kapillaren. Lipoblasten mit einer oder mehreren Vakuolen wurden häufig, jedoch nicht in allen Punktaten gefunden. Ihre diagnostische Bedeutung für die Differentialdiagnose wird diskutiert.     

Role of fine needle aspiration cytology in the diagnosis and management of Warthin’s tumour of the salivary glands

J. M. Viguer, B. Vicandi, J. A. Jiménez‐Heffernan, P. López‐Ferrer, P. González‐Peramato and C. Castillo
Role of fine needle aspiration cytology in the diagnosis and management of Warthin’s tumour of the salivary glands Objective: Local excision surgical procedures and non‐surgical conservative management are considered alternatives to superficial parotidectomy in the treatment and management of Warthin’s tumour (WT). Such therapeutic alternatives demand accurate diagnosis. In order to determine whether fine needle aspiration cytology (FNAC) is capable of rendering such a minimally invasive diagnosis, we evaluated its accuracy and diagnostic parameters in a large series of histologically proven cases of WT. Methods: A cytohistological study of 116 salivary tumours from 110 patients (four WT were bilateral) with a histological or cytological diagnosis of WT. Results: Histology confirmed the cytological diagnosis in 103 of 114 tumours (90.4%). Two tumours were incorrectly diagnosed on cytology as WT. In 11 cases of WT there was an erroneous or non‐representative cytological diagnosis. The sensitivity was 90.4%, and positive predictive value 98.1%. Regarding malignancy, there were three misdiagnoses. One tumour diagnosed as WT was a low‐grade mucoepidermoid carcinoma. Two cases considered ‘suspicious of squamous cell carcinoma’ corresponded to WT. After review, 81.3% of the cases of WT were considered typical and 18.7% non‐typical; all misdiagnoses were in the latter group. Cytological difficulties could be divided into three areas: (i) absence of one or more diagnostic components; (ii) ‘squamoid’ pattern; and (iii) mucinous metaplasia. Degenerated oncocytes were present in 65% of cases. Conclusions: FNAC offers the possibility of a reliable diagnosis of WT. Pathologists must pay attention to the squamous appearance of degenerated oncocytes. Cytology, when coupled with clinical and image findings, may permit conservative tumour management.     

Fine needle aspiration cytology of palatine tonsils: a study of 112 consecutive adult tonsillectomies

M. J. Ashraf, N. Azarpira, B. Nowroozizadeh, M. Shishegar, B. Khademi, A. Faramarzi, S. B. Hashemi, A. Hakimzadeh and E. Abedi
Fine needle aspiration cytology of palatine tonsils: a study of 112 consecutive adult tonsillectomies Objective: To study fine needle aspiration cytology (FNAC) findings of tonsillar lesions with histological controls and to assess its role in the diagnostic evaluation of tonsillectomy specimens. Methods: This study consisted of 112 cases that required tonsillectomy, comprising 55 (49.1%) men and 57 (50.9%) women. The ages ranged between 20 and 62 years. The clinical diagnosis in 101 cases was chronic tonsillitis, whereas 11 were suspected of neoplasia. FNAC was performed before tonsillectomy under general or local anaesthesia or on fresh specimens using a 21‐G needle. The smears were stained using Wright–Giemsa and Papanicolaou methods. Histological examination was carried out on surgical specimens of all cases and, when required, immunohistochemistry was performed on histological sections. The diagnostic outcomes between FNAC and surgical biopsy were compared. Results: In this study, 106 cases were diagnosed as chronic tonsillitis/follicular hyperplasia, four cases as non‐Hodgkin’s lymphoma, one as Hodgkin’s lymphoma and one as monophasic synovial sarcoma. All malignant cases were diagnosed by FNAC, but synovial sarcoma was incorrectly diagnosed as squamous cell carcinoma. Five cases clinically suspected of neoplasia were correctly diagnosed as chronic tonsillitis on cytology. Conclusion: Tonsillar aspiration is a safe procedure and is useful in the evaluation of tonsillectomy specimens. However, ancillary tests on cytological material are often needed when neoplasia is suspected and would help clinical management and allow histological examination of cases diagnosed cytologically as lymphoma.     

Prediction of aggressiveness of gastrointestinal stromal tumours based on immunostaining with bcl-2, Ki-67 and p53

OBJECTIVE: While the use of fine needle aspiration (FNA) in the diagnosis of gastrointestinal stromal tumours (GISTs) is well-established, it can be difficult to predict the prognosis of GIST based on morphology alone. The objective of the current study was to determine if expression of bcl-2, Ki-67 and p53 correlated with the outcome of GISTs based on cytological material. METHODS: Cell-blocks from 14 GISTs diagnosed by FNA were retrieved. Immunostaining was performed with antibodies against bcl-2, Ki-67 and p53. All cytological diagnoses were confirmed by positive immunostaining with c-kit and/or subsequent histological evaluation. Positivity for bcl-2, Ki-67 and p53 was defined as the presence of > or =10% cytoplasmic staining, > or =5% nuclear staining and > or =5% nuclear staining respectively. RESULTS: The 14 patients consisted of seven males and seven females with a mean age of 58 years. The average follow-up interval was 46 months. Six had a benign course and eight developed recurrences/metastases. Thirteen (93%) cases showed positive staining for bcl-2. Positive Ki-67 and p53 staining was noted in one (7%) and seven (50%) cases respectively. The difference in staining for p53 between aggressive and non-aggressive GISTs was statistically significant. No statistically significant difference was noted for bcl-2 staining or Ki-67 labelling index between the two groups. CONCLUSIONS: According to our observations, p53 immunostaining may be useful in predicting the outcome of GIST diagnosed by FNA; Ki-67 and bcl-2 are not useful as prognostic markers for GIST in FNA specimens.     

Histoplasmosis: cytodiagnosis and review of literature with special emphasis on differential diagnosis on cytomorphology

N. Gupta, S. K. Arora, A. Rajwanshi, R. Nijhawan and R. Srinivasan
Histoplasmosis: cytodiagnosis and review of literature with special emphasis on differential diagnosis on cytomorphology Background: Human infection with Histoplasma capsulatum runs the gamut from asymptomatic to disseminated disease. In immunocompromised patients, a tiny inoculum can lead to widespread disseminated infection. Early diagnosis and initiation of treatment is therefore important. Objective: To review the cases of histoplasmosis diagnosed on fine needle aspiration cytology (FNAC) and to discuss the clinical presentation, associated inflammatory response, load of organisms and differential diagnosis on cytomorphology in these cases. Methods: Retrospective review of seven cases of histoplasmosis at a tertiary‐care centre during the period from 1998 to 2009 was performed. Clinical presentation along with cytomorphological features were studied and discussed in detail. Results: The mean age of patients was 48.6 years and six out of seven were male. History of immunodeficiency (HIV) was available in five cases. Six patients presented with peripheral and/or abdominal lymphadenopathy. One patient had nodular shadows in both lungs and two also had skin lesions. On cytological smears, a variable load of uniform round to oval, about 2–4 μm in diameter, budding yeasts were seen intracellularly (within histiocytes) as well as extracellularly. In one case (HIV positive), these organisms were also seen within neutrophil polymorphonuclear leucocytes. In two cases, an inflammatory response in the form of epithelioid cell granulomas along with multinucleated giant cells was seen. Conclusions: FNAC is a reliable tool to recognize infection with H. capsulatum in tissues. This infection can cause a variable inflammatory response, which should be considered while reporting on such cases.     

Angiosarcoma in FNA smears: diagnostic accuracy,morphology, immunocytochemistry and differential diagnoses

?. Pohar‐Marin?ek and J. Lamovec Angiosarcoma in FNA smears: diagnostic accuracy, morphology, immunocytochemistry and differential diagnoses Objective: The aim of our study was to analyse the diagnostic accuracy in recognizing angiosarcoma from fine needle aspiration (FNA) samples and to determine morphological features of angiosarcoma in cytology. Methods: FNA samples from 18 histologically confirmed angiosarcomas obtained between 1985 and 2009 were included in the study. Original cytological diagnoses were retrieved, smears reviewed and morphological features analysed: cellularity, smear pattern, cell morphology, contents of background. Outcome of immunocytochemistry was noted and additional reactions performed if material was available. Results: There were 13 primary angiosarcomas and five recurrent tumours; nine tumours were epithelioid. Twelve tumours were cytologically diagnosed as malignant, three as suspicious and three were judged unsatisfactory. Only two primary tumours were diagnosed as vascular. According to morphology, tumours were divided into those with predominantly epithelioid cells and those with predominantly spindle cells. Within these two groups were variations due to grade of tumour. Cytomorphology did not correlate well with histology in mixed and spindle cell types of angiosarcomas. Immunocytochemistry was applied in seven cases, specific vascular marker CD31 only twice at the time of diagnosis and three times retrospectively. Conclusions: Angiosarcomas are difficult to recognize on FNA smears when they lack the typical dual, spindle and epithelioid cell population and when they occur in internal organs where carcinomas are more common. Very few reliable data are available concerning specificity of CD31 on cytological material.     

The diagnostic value of fine needle aspiration cytology (FNAC) in the assessment of palpable supraclavicular lymph nodes: a study of 218 cases

The aim of this study was to evaluate the diagnostic value of fine needle aspiration cytology (FNAC) in the assessment of palpable supraclavicular lymph nodes. The material was analysed in 218 cases with enlarged supraclavicular lymph nodes in which FNAC was performed by the conventional method. In all cases cytological examination was performed on-site after staining the smears by the Papanicolaou method. In addition, air-dried smears, fixed smears, filter preparations from needle washings and cell blocks were studied. The FNAC diagnosis was supported by examining cell blocks which added the reliability of histological architecture; further support was obtained by tissue biopsy and/or comparison with the primary tumour in some of the cases. Eleven cases were diagnosed as inflammatory lesions and 41 cases were unsatisfactory because of scanty/acellular samples (despite two to three repeat samplings). However, in five of these, malignant tumours were later found on biopsy, which was done for persistent enlargement of the supraclavicular lymph node(s). Fifty-three cases were diagnosed as negative for malignancy (normal cellular elements, n=15; reactive elements, n=38) and 12 cases were suspicious of malignancy. In 11 cases a diagnosis of lymphoma was made on histology and in 90 cases metastatic tumours were diagnosed. The overall sensitivity was 92.7%, specificity 98.5%, positive predictive value 97.3% and the negative predictive value was 94.8%. Based on our study we feel that FNAC of palpable supraclavicular lymph nodes as a first line of investigation is a cost-effective procedure and is not only useful in the diagnosis of various lesions but can also help in deciding on appropriate management. Furthermore, the histological architecture from cell blocks can be correlated with cytology, and such material can be used for appropriate histochemical and immunomarker studies, which can be useful in enhancing the diagnosis.     

Warthin''s tumour: unusual vs. common morphological findings in fine needle aspiration biopsies

Fine needle aspiration biopsies (FNA) of 47 Warthin's tumours confirmed by histology were re-evaluated for cytomorphological findings. The majority of aspirates (37/47) contained a typical background with proteinaceous substance and cell debris, along with cellular elements represented by oncocytic, lymphoid, and mast cells with degranulated cytoplasm. Uncommon cellular findings were true squamous cells (1/47), atypical cells with vacuoles (1/47), osteoclastic giant cells (1/47), epithelioid cells (1/47), mast cells with preserved granules in cytoplasm (3/47), and siderophages (4/47). Uncommon findings in the background were corpora amylacea-like structures and homogeneous bright red droplets. Squamous cells and atypical cells with vacuoles caused diagnostic difficulties in distinguishing a Warthin's tumour from a squamous cell or mucoepidermoid carcinoma. However, other unusual cellular and background findings were not worrying; therefore, they are merely regarded as a curiosity in the cytomorphological appearance of the tumour.     

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.     

The cytomorphologic spectrum of Wilms tumour on fine needle aspiration: a single institutional experience of 110 cases

A. Nayak, V.K. Iyer and S. Agarwala
The cytomorphologic spectrum of Wilms tumour on fine needle aspiration: a single institutional experience of 110 cases Objective: To analyse the cytomorphologic spectrum of Wilms tumour (WT) on aspirates, the largest series reported to date. Study design: Adequate aspirates from paediatric renal tumours over a period of 17 years were reviewed and selected if subsequent excision showed WT or aspirates were diagnostic for WT and clinical/radiological evidence consistent with that diagnosis. Smears were re‐examined for the proportion of components, degree of pleomorphism and mitosis. Results: Of 110 aspirates, smears were triphasic in 44 (40.0%), biphasic (blastema and tubules) in 36 (32.7%) and monophasic (blastema alone) in 30 (27.3%). Stromal predominance was seen in 11 aspirates (10.0%) and five showed rhabdomyoblastic differentiation; all 11 were triphasic. Mean mitotic rate was 9.3/5000 cells (range 4–39/5000). Nuclear atypia not amounting to anaplasia and without atypical mitoses was seen in 15 (13.6%); these presented diagnostic problems. Two aspirates (1.8%) were considered anaplastic (unfavourable), both having atypical mitoses. Criteria similar to histology (i.e. 3‐fold or more variation in nuclear size, marked hyperchromasia with bizarre nuclei and atypical mitoses in a biphasic or triphasic aspirate) helped in distinguishing anaplastic WT. Histopathological correlation in 67 cases showed good correlation of blastemal predominance, stromal predominance and anaplastic histology with the corresponding cytology. However, 9/27 (33.3%) triphasic tumours had only blastemal cells on corresponding aspiration because of sampling error. Cytokeratin was positive in 4 of 20 aspirates with blastema alone. Conclusions: Aspirates from WT were triphasic or biphasic in the majority (72.7%), permitting cytological diagnosis, which was improved by cytokeratin immunocytochemistry. Blastemal and stromal predominance on histology correlated well with cytology, but many triphasic tumours showed only blastema on aspiration. Anaplastic WT can be detected on aspirates using criteria similar to histology.     

The role of liquid-based cytology in the investigation of thyroid lesions

Objective:  This study investigates the role of liquid-based cytology by ThinPrep^® technique in the detection of thyroid lesions.
Methods:  In all, 252 specimens from 157 patients for pre-operative evaluation of thyroid nodules, prepared by the ThinPrep^®, were examined. In all cases thyroidectomy followed the initial cytological evaluation. All cytological diagnoses were correlated to the histological ones.
Results:  According to our findings, a sensitivity of 87.80%, a specificity of 99.50%, a positive predictive value of 97.30%, a negative predictive value of 97.56% and an overall accuracy of 97.52% were observed in fine needle aspiration cytology in correlation to the histological diagnosis after thyroidectomy.
Conclusions:  ThinPrep^® technique is a valid method for the pre-operative cytological diagnosis of thyroid nodules, offering the possibility of ancillary techniques, such as immunocytochemical and molecular methods and can, therefore, be potentially complementary to histological evaluation for further investigation of follicular lesions.