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DOI: 10.1055/s-0040-1715148
The Role of FNAC in the Diagnosis and Management of Warthin Tumour: Analysis of 74 Cases
Abstract
Introduction After pleomorphic adenoma, Warthin tumor gets its popularity as the second most common benign neoplasm of the parotid gland. Fine-needle aspiration cytology (FNAC) is the most cost-effective and minimally-invasive way to determine the histological character of a parotid gland tumor.
Objective To determine the accuracy of FNAC in the diagnosis of Warthin Tumour.
Methods A retrospective study conducted between 2014 and 2018. Out of 243 FNACs performed for parotid lesions, a histopathological correlation was established in 74 cases to reveal the accuracy of FNAC in the diagnosis of Warthin tumor.
Results A total of 243 FNACs of parotid lesions were performed, and a histopathological correlation was established in 74 (30.4%) cases. Later on, we confirmed that 16 (21.6%) out of these 74 patients had cases of Warthin tumor. In total, 15 (20.3%) out of those 74 cases were confirmed as Warthin tumors on the initial cytology, which revealed a true positive concordance between the cytology and the final histological diagnosis; 55/74 (74%) were true negative results; on the other hand, 1/74 (1.4%) was a false negative, and 3/74 (4.1%) were false positive results. The sensitivity of the FNAC in the diagnosis of Warthin tumor was of 93%, while the specificity was of 94.8%, and the accuracy, of 94.6%.
Conclusion In the present study, FNAC had a high diagnostic accuracy, reaching 94%.
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Introduction
After pleomorphic adenoma, Warthin tumor (WT) gets its popularity as the second most common benign neoplasm of the parotid gland. It accounts for 15% to 30% of all parotid tumors.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] Among its unique features, especially in the fifth and sixth decades of life, the tumor tends to affect more the population of male smokers.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] It typically presents as an asymptomatic, slow-growing mass, usually located in the tail (inferior) portion of the parotid gland, and multicentric occurrence is observed more often with WT than with any other salivary-gland tumor.[3] These tumors have a tendency toward multiplicity and bilaterality.[6] [7] [8] [9] [10] [11] Recently, many reports[7] [8] [9] [10] have presented patients with clinical features that differ from that of the traditional tumors in some way, with an increasing incidence among females, higher rates of tumor multiplicity and bilaterality,[7] [8] [9] and superadded differences in the regional, national and racial occurrences.[10] With less than 1% of risk of malignant evolution, WT differs from pleomorphic adenomas.[12] This makes surgery not the first-line treatment when the diagnosis is certain preoperatively as it is harboring the risk of facial nerve injury.[13] [14]
Warthin tumor was previously called cystadenoma papilliferum, a term coined by Alfred Warthin in 1929. It is a peculiar entity with two distinct cellular components in variable proportions. Its origin is also debatable, with one theory suggesting it originates from epithelial cell rest in the lymph node, and another stating that it is an adenoma with lymphocytic infiltration. Subsequent molecular studies[5] [6] have shown that it is not a true neoplasm. The most accepted hypothesis is that it originates from salivary-duct inclusions in the lymph nodes.[15]
Salivary-gland lesions have been fairly accurately diagnosed on fine-needle aspiration cytology (FNAC), with an accuracy ranging from 74% to 97%.[] [] [16-18] However, the diagnostic accuracy of FNAC for WT has been a source of concern and a subject of debate.[19] [20] [21] [22]
Fine-needle aspiration cytology is the most cost-effective and minimally-invasive way to determine the histological character of a parotid-gland tumor. But it is not always conclusive, because the material may be insufficient. Furthermore, in the case of WT, which contains inflammatory cells, FNAC may be responsible for an inflammatory flare, with pain and an increase in the volume of the lesion.[23]
Fine-needle aspiration (FNA) is a valuable tool in the diagnosis of head and neck lesions, with a proven high accuracy.[24] [25] [26] This is particularly true for salivary-gland neoplasms, because the FNA diagnosis guides the decision of the clinician regarding the management of the patients. In most patients, careful interpretation of the cytomorphologic findings renders an accurate diagnosis, enabling the conservative management of the patients with benign lesions.[25]
Warthin tumor has a cystic appearance, with a double layer of oncocytes surrounding a lymphoid stroma. There are two main cellular components: the epithelial and lymphoid components. The typical features on cytology include oncocytic cells in cohesive, monolayered sheets, background lymphocytes, and amorphous, cystic debris.[25] [26] [27]
Despite its well-defined histological appearance, the often variegated cytomorphology of WT may lead to an erroneous cytopathological interpretation. We conducted the study to determine the accuracy of FNAC in the diagnosis of WT.
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Methods
A retrospective study of patient records was performed between 2014 and 2018 after a formal review and waiver by the institutional review board (IRB). A total number of 243 FNACs were performed for parotid lesions. A histopathological correlation was established in 74 out of these 243 cases to reveal the accuracy of FNAC in the diagnosis of WT tumor.
Fine-needle aspiration biopsy (FNAB) was performed by a cytopathologist using a 23-gauge fine needle attached to a 10-ml plastic syringe and employing a Cameco gun (Precision Dynamics Corporation, Valencia, CA, US). Slides were air-dried for Diff-Quik (MICROPTIC S.L., Barcelona, Spain) staining, and an on-site, provisional cytopathological diagnosis was rendered on all slides. Additional smears were prepared and fixed immediately in 95% ethanol for subsequent Papanicolaou staining. In a few cases, needle rinses with balanced salt solution were used to make paraffin cell blocks, and 4-mm thin sections were stained with hematoxylin and eosin. A histopathological correlation of the result of the FNAB with the surgical specimen was established to confirm the accuracy of the cytological diagnosis.
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Results
A total of 243 FNACs for parotid lesions were performed, and a histopathological correlation was established in 74 (30.4%) cases. Later, we confirmed that 16 (21.6%) out of these 74 operated patients had cases of WT, 15 (20.3%) of which were confirmed on the initial cytology, which revealed a true positive concordance between the cytology and the final histological diagnosis; 55/74 (74%) were true negative results; on the other hand, 1/74 (1.4%) was a false negative result, and 3/74 (4.1%) were false positive results ([Table 1]). The sensitivity of the FNAC in the diagnosis of WT was of 93%, while the specificity was of 94.8%, and the accuracy, 94.6% ([Table 2]).
Fine-needle aspiration cytology |
% |
---|---|
Sensitivity |
93 |
Specificity |
94.8 |
Accuracy |
94.6 |
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Discussion
Of all salivary-gland tumors present in the patients in the sample, 5% to 10% were WTs.[19] It is an asymptomatic disease, but it may present with pain because of the effects of the pressure exerted due to the rapid growth or because of the superadded inflammation.[15] The group mostly affected is comprised of male patients at an older age, but nowadays, due to the rise in the habit of smoking, women are also being affected.[15] [19] Although the parotid gland is the main site of origin, WT is also found in the submandibular gland.[15] [19]
Fine-needle aspiration cytology of the salivary-gland lesions has been shown to reduce the number of patients undergoing surgery by ∼ 30%.[28] [29] For this reason, FNAC is a widely-used procedure. Through FNA, a salivary gland lesion can be classified into one of two categories:[1] inflammatory or non-neoplastic, and[2] neoplastic. This simple triage approach is often appropriate, and may determine the medical or surgical therapy. However, further diagnostic accuracy is desirable, and can be achieved with knowledge of the pitfalls and limitations.[30]
There are few case reports[20] [22] [30] demonstrating a malignant tumor adjacent to a benign Warthin lesion. Most of these cases were associated with previous radiotherapy.[31] Obviously, misdiagnosis of a malignant tumor in patients with preoperative benign cytological examination falsely interpreted as a WT is the error that must be avoided. The question is whether this error is of practical concern in a large hospital with experienced cytopathologists. This concern has not been specifically addressed.[32]
In a study by Parwani and Ali,[21] 74% (31) of the patients with a histologically-confirmed WT had the same preoperative cytological diagnosis. Similar findings were presented by Ballo et al,[19] who analyzed 16 patients; in their study, the cytological accuracy was of 81% (3 cases were submitted to preoperative FNAs, which suggested a malignant tumor).[19] In the study by Flezar and Pogacnik,[33] 37 (79%) out of 47 patients had a correct FNA diagnosis confirmed by histology.[33] Nir et al[32] described an accuracy of the FNAC of 78.7% in 48 out of 61 patients who had diagnoses of WT, and Lewis et al[34] reported that 21 (65%) out of 32 patients had a preoperative diagnosis of WT tumor. In the present study, 15 (93.8%) out of 16 cases operated for WT had a preoperative correlation established by FNAC, while 1 (6.2%) out of these16 cases (6.2%) was FNAC as pleomorphic preoperatively. As results, we had a sensitivity of 93%, a specificity of 94.8%, and an accuracy of 94.6%; this was incompatible with the results obtained by Dong et al:[35] sensitivity of 60.2%, specificity of 0%, and accuracy of 60.2%, while Neelam and Borah[30] obtained an accuracy of 79%. Based on multiple previous studies,[19] [21] [34] [36] the sensitivity, specificity and diagnostic accuracy of FNAC in diagnosing WT ranges from 74% to 100%. The two main sources of error include failure to obtain a representative sample and the variable cytological appearance of WT.[21] [34] [37] The former can be minimized by recruiting a cytopathologist to perform the procedure. This has the added advantage of limiting histological alterations after biopsy, another major operator-related problem.[37]
In the present study, there were four cases with revision of the results, two by core biopsy and two by FNAC, which confirmed the diagnosis of WT before proceeding to surgery. The need for preoperative FNA is a debatable issue. It is considered an acceptable surgical practice to excise parotid masses without a preoperative FNA. We are of the opinion that this practice may be outmoded, as a preoperative FNA may obviate the need for surgery of a WT, which is the second most common benign parotid tumor. In any case, cytological interpretations should be considered in the context of the history, physical examination findings, and imaging exams. In any case in which the clinical judgment is of suspicion of a malignant lesion, surgical excision is mandatory, regardless of the result of the FNA.[32]
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Conclusion
In the present study, the diagnostic accuracy of the FNAC was high, reaching 94%. In addition, the accuracy increased with the increase in sample size with a multicenter comprehensive study. Revision of the results assists in the diagnostic accuracy and makes it possible to avoid unnecessary operations.
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Summary
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Warthin tumor is the second most common benign parotid tumor.
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In any case, cytological interpretations should be considered in the context of the history, physical examination findings, and imaging exams.
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In any case in which the clinical judgment is of suspicion of a malignant lesion, surgical excision is mandatory, regardless of the result of the FNA.
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The diagnostic accuracy of the FNAC was high, reaching 94%.
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In addition, the accuracy increased with the increase in the sample size with a multicenter comprehensive study.
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Die Autoren geben an, dass kein Interessenkonflikt besteht.
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References
- 1 Guntinas-Lichius O, Klussmann JP, Wittekindt C, Stennert E. Parotidectomy for benign parotid disease at a university teaching hospital: outcome of 963 operations. Laryngoscope 2006; 116 (04) 534-540
- 2 Renehan A, Gleave EN, Hancock BD, Smith P, McGurk M. Long-term follow-up of over 1000 patients with salivary gland tumours treated in a single centre. Br J Surg 1996; 83 (12) 1750-1754
- 3 Maiorano E, Lo Muzio L, Favia G, Piattelli A. Warthin's tumour: a study of 78 cases with emphasis on bilaterality, multifocality and association with other malignancies. Oral Oncol 2002; 38 (01) 35-40
- 4 Teymoortash A, Krasnewicz Y, Werner JA. Clinical features of cystadenolymphoma (Warthin's tumor) of the parotid gland: a retrospective comparative study of 96 cases. Oral Oncol 2006; 42 (06) 569-573
- 5 Teymoortash A, Werner JA. Tissue that has lost its track: Warthin's tumour. Virchows Arch 2005; 446 (06) 585-588
- 6 Teymoortash A, Schrader C, Shimoda H, Kato S, Werner JA. Evidence of lymphangiogenesis in Warthin's tumor of the parotid gland. Oral Oncol 2007; 43 (06) 614-618
- 7 Espinoza S, Felter A, Malinvaud D. et al. Warthin's tumor of parotid gland: Surgery or follow-up? Diagnostic value of a decisional algorithm with functional MRI. Diagn Interv Imaging 2016; 97 (01) 37-43
- 8 Schwalje AT, Uzelac A, Ryan WR. Growth rate characteristics of Warthin's tumours of the parotid gland. Int J Oral Maxillofac Surg 2015; 44 (12) 1474-1479
- 9 Patel DK, Morton RP. Demographics of benign parotid tumours: Warthin's tumour versus other benign salivary tumours. Acta Otolaryngol 2016; 136 (01) 83-86
- 10 Lee DH, Yoon TM, Lee JK, Lim SC. Surgical treatment outcomes of patients with bilateral warthin tumors in the parotid gland. Indian J Otolaryngol Head Neck Surg 2014; 66 (Suppl. 01) 303-306
- 11 Peter Klussmann J, Wittekindt C, Florian Preuss S, Al Attab A, Schroeder U, Guntinas-Lichius O. High risk for bilateral Warthin tumor in heavy smokers--review of 185 cases. Acta Otolaryngol 2006; 126 (11) 1213-1217
- 12 Som PM, Brandwein MS. Salivary glands: anatomy and pathology. In: Som PM, Curtin HD. , editors. Head and neck imaging. 4th ed. St. Louis, Mo: Mosby; 2005: 2003-133
- 13 Bradley PT, Paleri V, Homer JJ. Consensus statement by otolaryngologists on the diagnosis and management of benign parotid gland disease. Clin Otolaryngol 2012; 37 (04) 300-304
- 14 Yu GY, Ma DQ, Liu XB, Zhang MY, Zhang Q. Local excision of the parotid gland in the treatment of Warthin's tumour. Br J Oral Maxillofac Surg 1998; 36 (03) 186-189
- 15 Faur A, Lazăr E, Cornianu M, Dema A, Vidita CG, Găluşcan A. Warthin tumor: a curious entity--case reports and review of literature. Rom J Morphol Embryol 2009; 50 (02) 269-273
- 16 Jayaram G, Verma AK, Sood N, Khurana N. Fine needle aspiration cytology of salivary gland lesions. J Oral Pathol Med 1994; 23 (06) 256-261
- 17 Naz S, Hashmi AA, Khurshid A. et al. Diagnostic role of fine needle aspiration cytology (FNAC) in the evaluation of salivary gland swelling: an institutional experience. BMC Res Notes 2015; 8: 101
- 18 Klijanienko J, Vielh P. Fine-needle sampling of salivary gland lesions. II. Cytology and histology correlation of 71 cases of Warthin's tumor (adenolymphoma). Diagn Cytopathol 1997; 16 (03) 221-225
- 19 Ballo MS, Shin HJ, Sneige N. Sources of diagnostic error in the fine-needle aspiration diagnosis of Warthin's tumor and clues to a correct diagnosis. Diagn Cytopathol 1997; 17 (03) 230-234
- 20 Verma K, Kapila K. Salivary gland tumors with a prominent oncocytic component. Cytologic findings and differential diagnosis of oncocytomas and Warthin's tumor on fine needle aspirates. Acta Cytol 2003; 47 (02) 221-226
- 21 Parwani AV, Ali SZ. Diagnostic accuracy and pitfalls in fine-needle aspiration interpretation of Warthin tumor. Cancer 2003; 99 (03) 166-171
- 22 Chakrabarti I, Basu A, Ghosh N. Oncocytic lesion of parotid gland: A dilemma for cytopathologists. J Cytol 2012; 29 (01) 80-82
- 23 Suzuki K, Iwai H, Kaneko T, Sakaguchi M, Hoshino S, Inaba M. Induction of parotitis by fine-needle aspiration in parotid Warthin's tumor. Otolaryngol Head Neck Surg 2009; 141 (02) 282-284
- 24 So T, Sahovaler A, Nichols A. et al. Utility of clinical features with fine needle aspiration biopsy for diagnosis of Warthin tumor. J Otolaryngol Head Neck Surg 2019; 48 (01) 41
- 25 Yariv O, Popovtzer A, Wasserzug O. et al. Usefulness of ultrasound and fine needle aspiration cytology of major salivary gland lesions. Am J Otolaryngol 2020; 41 (01) 102293
- 26 Suzuki M, Kawata R, Higashino M. et al. Values of fine-needle aspiration cytology of parotid gland tumors: A review of 996 cases at a single institution. Head Neck 2019; 41 (02) 358-365
- 27 Cohen MB, Reznicek MJ, Miller TR. Fine-needle aspiration biopsy of the salivary glands. Pathol Annu 1992; 27 (Pt 2): 213-245
- 28 Qizilbash AH, Sianos J, Young JEM, Archibald SD. Fine needle aspiration biopsy cytology of major salivary glands. Acta Cytol 1985; 29 (04) 503-512
- 29 Layfield LJ, Glasgow BJ. Diagnosis of salivary gland tumors by fine-needle aspiration cytology: a review of clinical utility and pitfalls. Diagn Cytopathol 1991; 7 (03) 267-272
- 30 Neelam S, Borah P. Warthin tumor: Cytohistological spectrum with emphasis on diagnostic difficulties. Diagn Cytopathol 2018; 46 (07) 613-619
- 31 Seifert G, Bull HG, Donath K. Histologic subclassification of the cystadenolymphoma of the parotid gland. Analysis of 275 cases. Virchows Arch A Pathol Anat Histol 1980; 388 (01) 13-38
- 32 Nir H, Cohen J, Neuman T, Weinberger JM, Eliashar R. Is surgery for an FNA proven Warthins Tumor Passé?. J Cancer Ther Res 2012; •••: 1-4
- 33 Flezar M, Pogacnik A. Warthin's tumour: unusual vs. common morphological findings in fine needle aspiration biopsies. Cytopathology 2002; 13 (04) 232-241
- 34 Lewis DR, Webb AJ, Lott MF, Brookes ST, Farndon JR. Improving cytological diagnosis and surgical management of parotid adenolymphoma. Br J Surg 1999; 86 (10) 1275-1279
- 35 Dong HL, Yoon TM, Lee JK, Lim SC. Surgical treatment strategy in Warthin Tumor of the parotid gland. BJORL 2019; 85 (05) 546-550
- 36 Fulciniti F, Califano L, Zupi A, Vetrani A. Accuracy of fine needle aspiration biopsy in head and neck tumors. J Oral Maxillofac Surg 1997; 55 (10) 1094-1097
- 37 Filopoulos E, Angeli S, Daskalopoulou D, Kelessis N, Vassilopoulos P. Pre-operative evaluation of parotid tumours by fine needle biopsy. Eur J Surg Oncol 1998; 24 (03) 180-183
Address for correspondence
Publikationsverlauf
Eingereicht: 11. Mai 2020
Angenommen: 21. Juni 2020
Artikel online veröffentlicht:
24. September 2020
© 2020. Fundação Otorrinolaringologia. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commecial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)
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References
- 1 Guntinas-Lichius O, Klussmann JP, Wittekindt C, Stennert E. Parotidectomy for benign parotid disease at a university teaching hospital: outcome of 963 operations. Laryngoscope 2006; 116 (04) 534-540
- 2 Renehan A, Gleave EN, Hancock BD, Smith P, McGurk M. Long-term follow-up of over 1000 patients with salivary gland tumours treated in a single centre. Br J Surg 1996; 83 (12) 1750-1754
- 3 Maiorano E, Lo Muzio L, Favia G, Piattelli A. Warthin's tumour: a study of 78 cases with emphasis on bilaterality, multifocality and association with other malignancies. Oral Oncol 2002; 38 (01) 35-40
- 4 Teymoortash A, Krasnewicz Y, Werner JA. Clinical features of cystadenolymphoma (Warthin's tumor) of the parotid gland: a retrospective comparative study of 96 cases. Oral Oncol 2006; 42 (06) 569-573
- 5 Teymoortash A, Werner JA. Tissue that has lost its track: Warthin's tumour. Virchows Arch 2005; 446 (06) 585-588
- 6 Teymoortash A, Schrader C, Shimoda H, Kato S, Werner JA. Evidence of lymphangiogenesis in Warthin's tumor of the parotid gland. Oral Oncol 2007; 43 (06) 614-618
- 7 Espinoza S, Felter A, Malinvaud D. et al. Warthin's tumor of parotid gland: Surgery or follow-up? Diagnostic value of a decisional algorithm with functional MRI. Diagn Interv Imaging 2016; 97 (01) 37-43
- 8 Schwalje AT, Uzelac A, Ryan WR. Growth rate characteristics of Warthin's tumours of the parotid gland. Int J Oral Maxillofac Surg 2015; 44 (12) 1474-1479
- 9 Patel DK, Morton RP. Demographics of benign parotid tumours: Warthin's tumour versus other benign salivary tumours. Acta Otolaryngol 2016; 136 (01) 83-86
- 10 Lee DH, Yoon TM, Lee JK, Lim SC. Surgical treatment outcomes of patients with bilateral warthin tumors in the parotid gland. Indian J Otolaryngol Head Neck Surg 2014; 66 (Suppl. 01) 303-306
- 11 Peter Klussmann J, Wittekindt C, Florian Preuss S, Al Attab A, Schroeder U, Guntinas-Lichius O. High risk for bilateral Warthin tumor in heavy smokers--review of 185 cases. Acta Otolaryngol 2006; 126 (11) 1213-1217
- 12 Som PM, Brandwein MS. Salivary glands: anatomy and pathology. In: Som PM, Curtin HD. , editors. Head and neck imaging. 4th ed. St. Louis, Mo: Mosby; 2005: 2003-133
- 13 Bradley PT, Paleri V, Homer JJ. Consensus statement by otolaryngologists on the diagnosis and management of benign parotid gland disease. Clin Otolaryngol 2012; 37 (04) 300-304
- 14 Yu GY, Ma DQ, Liu XB, Zhang MY, Zhang Q. Local excision of the parotid gland in the treatment of Warthin's tumour. Br J Oral Maxillofac Surg 1998; 36 (03) 186-189
- 15 Faur A, Lazăr E, Cornianu M, Dema A, Vidita CG, Găluşcan A. Warthin tumor: a curious entity--case reports and review of literature. Rom J Morphol Embryol 2009; 50 (02) 269-273
- 16 Jayaram G, Verma AK, Sood N, Khurana N. Fine needle aspiration cytology of salivary gland lesions. J Oral Pathol Med 1994; 23 (06) 256-261
- 17 Naz S, Hashmi AA, Khurshid A. et al. Diagnostic role of fine needle aspiration cytology (FNAC) in the evaluation of salivary gland swelling: an institutional experience. BMC Res Notes 2015; 8: 101
- 18 Klijanienko J, Vielh P. Fine-needle sampling of salivary gland lesions. II. Cytology and histology correlation of 71 cases of Warthin's tumor (adenolymphoma). Diagn Cytopathol 1997; 16 (03) 221-225
- 19 Ballo MS, Shin HJ, Sneige N. Sources of diagnostic error in the fine-needle aspiration diagnosis of Warthin's tumor and clues to a correct diagnosis. Diagn Cytopathol 1997; 17 (03) 230-234
- 20 Verma K, Kapila K. Salivary gland tumors with a prominent oncocytic component. Cytologic findings and differential diagnosis of oncocytomas and Warthin's tumor on fine needle aspirates. Acta Cytol 2003; 47 (02) 221-226
- 21 Parwani AV, Ali SZ. Diagnostic accuracy and pitfalls in fine-needle aspiration interpretation of Warthin tumor. Cancer 2003; 99 (03) 166-171
- 22 Chakrabarti I, Basu A, Ghosh N. Oncocytic lesion of parotid gland: A dilemma for cytopathologists. J Cytol 2012; 29 (01) 80-82
- 23 Suzuki K, Iwai H, Kaneko T, Sakaguchi M, Hoshino S, Inaba M. Induction of parotitis by fine-needle aspiration in parotid Warthin's tumor. Otolaryngol Head Neck Surg 2009; 141 (02) 282-284
- 24 So T, Sahovaler A, Nichols A. et al. Utility of clinical features with fine needle aspiration biopsy for diagnosis of Warthin tumor. J Otolaryngol Head Neck Surg 2019; 48 (01) 41
- 25 Yariv O, Popovtzer A, Wasserzug O. et al. Usefulness of ultrasound and fine needle aspiration cytology of major salivary gland lesions. Am J Otolaryngol 2020; 41 (01) 102293
- 26 Suzuki M, Kawata R, Higashino M. et al. Values of fine-needle aspiration cytology of parotid gland tumors: A review of 996 cases at a single institution. Head Neck 2019; 41 (02) 358-365
- 27 Cohen MB, Reznicek MJ, Miller TR. Fine-needle aspiration biopsy of the salivary glands. Pathol Annu 1992; 27 (Pt 2): 213-245
- 28 Qizilbash AH, Sianos J, Young JEM, Archibald SD. Fine needle aspiration biopsy cytology of major salivary glands. Acta Cytol 1985; 29 (04) 503-512
- 29 Layfield LJ, Glasgow BJ. Diagnosis of salivary gland tumors by fine-needle aspiration cytology: a review of clinical utility and pitfalls. Diagn Cytopathol 1991; 7 (03) 267-272
- 30 Neelam S, Borah P. Warthin tumor: Cytohistological spectrum with emphasis on diagnostic difficulties. Diagn Cytopathol 2018; 46 (07) 613-619
- 31 Seifert G, Bull HG, Donath K. Histologic subclassification of the cystadenolymphoma of the parotid gland. Analysis of 275 cases. Virchows Arch A Pathol Anat Histol 1980; 388 (01) 13-38
- 32 Nir H, Cohen J, Neuman T, Weinberger JM, Eliashar R. Is surgery for an FNA proven Warthins Tumor Passé?. J Cancer Ther Res 2012; •••: 1-4
- 33 Flezar M, Pogacnik A. Warthin's tumour: unusual vs. common morphological findings in fine needle aspiration biopsies. Cytopathology 2002; 13 (04) 232-241
- 34 Lewis DR, Webb AJ, Lott MF, Brookes ST, Farndon JR. Improving cytological diagnosis and surgical management of parotid adenolymphoma. Br J Surg 1999; 86 (10) 1275-1279
- 35 Dong HL, Yoon TM, Lee JK, Lim SC. Surgical treatment strategy in Warthin Tumor of the parotid gland. BJORL 2019; 85 (05) 546-550
- 36 Fulciniti F, Califano L, Zupi A, Vetrani A. Accuracy of fine needle aspiration biopsy in head and neck tumors. J Oral Maxillofac Surg 1997; 55 (10) 1094-1097
- 37 Filopoulos E, Angeli S, Daskalopoulou D, Kelessis N, Vassilopoulos P. Pre-operative evaluation of parotid tumours by fine needle biopsy. Eur J Surg Oncol 1998; 24 (03) 180-183