| Abstract|| |
Background: To accost things in a particular disciple, egress related to Fine Needle Aspiration Cytology (FNAC) and to standardize reporting pattern, a framework “Milan System for Reporting Salivary Gland Cytopathology” (MSRSGC) has been sponsored. Aim: Aim of this study was to evaluate the potency of salivary gland FNAC reported under Milan guidelines, to calculate malignancy risk, and to compare the preoperative cytological diagnoses with the postoperative histopathological diagnoses. Settings and Design: This was a retrospective study over a period of 2 years (May 2016 to April 2018), which was classified according to Milan system and correlation with histopathology. Furthermore, the risk of malignancy was calculated for all the diagnostic categories. Materials and Methods: FNAC were analyzed on 105 patients with palpable salivary gland. Results were distributed into six categories. About 76 cases were surgically treated and resected tissues were submitted for histopathological examination. Statistical Analysis: The various diagnostic values of the procedure were calculated using the standard formula. Results: We reviewed 105 salivary gland FNA samples and recorded interpretations according to the proposed standardized six categories. Among them, category IV (neoplastic) had more cases (57.14%). The rates of malignancy in histology were as follows: (1) nondiagnostic, 0.0%; (2) nonneoplastic, 0.0%; (3) atypia of undermined significance, 50.00%; (4a) benign, 02.44%; (4b) uncertain malignant potential, 33.33%; (5) suspicious for malignancy, 100%; and (6) malignancy, 93.33%. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of Milan system came out to be 85.00%, 98.14%, 94.44%, 94.64%, and 94.59%, respectively. Conclusion: The six-tier diagnostic categories of the Milan system helps in triaging patients with salivary gland swelling and thus facilitate individualized management.
Keywords: Cytohistological correlation, diagnostic accuracy, Milan nomenclature, predictive value, rate of malignancy, salivary gland, sensitivity, specificity
|How to cite this article:|
Karuna V, Gupta P, Rathi M, Grover K, Nigam JS, Verma N. Effectuation to Cognize malignancy risk and accuracy of fine needle aspiration cytology in salivary gland using “Milan System for Reporting Salivary Gland Cytopathology”: A 2 years retrospective study in academic institution. Indian J Pathol Microbiol 2019;62:11-6
|How to cite this URL:|
Karuna V, Gupta P, Rathi M, Grover K, Nigam JS, Verma N. Effectuation to Cognize malignancy risk and accuracy of fine needle aspiration cytology in salivary gland using “Milan System for Reporting Salivary Gland Cytopathology”: A 2 years retrospective study in academic institution. Indian J Pathol Microbiol [serial online] 2019 [cited 2020 Sep 23];62:11-6. Available from: http://www.ijpmonline.org/text.asp?2019/62/1/11/251250
| Introduction|| |
Salivary gland lesions (SGL) represent 3%–6% of all tumors of the head and neck region. Proper management of these tumors requires an accurate diagnosis by the pathologist, radiologist, and clinicians. FNAC is a useful, simple, cost-effective, and minimal invasive procedure. There was varied nomenclature and reporting formats for SGL from two category schemes to five or more category schemes, which made it difficult for clinicians to interpret the reports.,, To make uniform reporting pattern, American Society of Cytopathology (ASC) and the International Academy of Cytology (IAC), gathered in September 2015 at the European Congress of Cytology, held in Milan, Italy, to propose Milan System, with the aim to produce a practical classification system that is user-friendly and internationally accepted. There were 40 participants from 14 countries. This system is based upon evidence from the literature as well as upon the experience of a multidisciplinary group of experts involved in the field of salivary gland cytopathology. Later on, a monograph “Milan System for Reporting Salivary Gland Cytopathology (MSRSGS),” which includes diagnostic criteria, explanatory notes, implied risk of malignancy (ROM), and a brief management plan for each diagnostic category was promulgated. This is a six-category scheme: A “neoplasm” category that is split into “benign” and “salivary gland neoplasm of uncertain malignant potential (SUMP).” Each category has an implied cancer risk, ranging from 0% to 67% for the “nondiagnostic” category to high 57%–100% for the “malignant” category. This study was carried out to classify salivary gland lesions under Milan counsel, to ascertain rate of malignancy and also to determine the diagnostic accuracy in and around our institute by correlating the cytohistopathological diagnoses on the resected specimens and biopsies.
| Materials and Methods|| |
A retrospective study was conducted on the all cases of salivary gland swelling (SGS) and went to the pathology department “between” May 2016 and April 2018. This study received approval from the Institutional Ethics Committee. Patients of all ages, either gender, and willing for participation were included and patients those suffering from psychiatric illness, surgical illness, and those were unwilling for FNAC excluded from this study. In duration of 2 years, total 105 cases of SGS in the parotid, submandibular, and other region were identified. After recording the relevant clinical details, FNA was performed under aseptic precaution using a 10 ml disposable syringe and 23/24 gauge needle without local anesthesia with informed consent. If the aspirate was insufficient, a repeat aspiration was done. The material was aspirated and the character was noted. Routine smears prepared, Giemsa staining was done on the air-dried smears while those fixed in 95% alcohol were stained by Papanicolaou's method. The results obtained on FNAC were divided into six categories as per Milan system: (1) nondiagnostic, (2) nonneoplastic, (3) atypia of undetermined significance (AUS), (4) neoplastic (benign and uncertain malignant potential [UMP]), (5) suspicious for malignancy (SFM), and (6) malignancy. For histopathology examination, 10% neutral buffer formalin fixed, surgically resected specimen and biopsy tissues were received, processed, and stained with H and E (hematoxylin and eosin). The rate of malignancy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were evaluated on the basis of final histopathological correlation. Results of cytology and histopathology were compared and ROM was calculated by dividing the total number of cases turned out to be malignant on histopathology in each category by number of cases in each category on cytology. For statistical calculations cytological diagnoses were classified as positive (malignancy) and negative (benign). Patients with negative cytological diagnosis but later diagnosed as cases of carcinoma histopathological examination were considered as false negative, whereas patients with positive cytological diagnosis but later diagnosed benign were taken as false positive. Histopathological report was considered as the gold standard.
| Results|| |
Of 105 patients, 73 (69.52%) were male and 32 (30.48%) of them were female. Highest incidence in male patient was found in 31- to 40-year age group comprising 19/73 (26.02%) cases of total and female was between 51 and 60 years comprising 08/32 (32.00%) cases of total. Overall highest incidence was found between 31 and 40 (23.80%) years age group as shown in [Table 1]. Male:female ratio was 2.2:1. Parotid gland was the most common site to be involved (N = 63; 59.05%) followed by submandibular gland (N = 33; 31.43%) and minor salivary gland (N = 10; 09.52%) [Table 2]. None of the cases of sublingual salivary gland lesions was observed in this study.
|Table 2: Distribution of 105 cases of salivary gland swellings on the basis of involved glands|
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The FNAC results were categorized into six groups of Milan system reporting of salivary glands and results as nondiagnostic in 03/105 (2.08%) cases, nonneoplastic in 17/105 (16.20%) cases, AUS in 03/105 (02.85%) cases, and neoplastic in 60/105 (57.14%) cases [benign: N =54/60; 51.43% and UMP: N =06/60; 04.76%]. SFM was noted in 05/105 (04.76%) cases and malignant in 17/105 (16.20%) cases. In nonneoplastic, benign and malignancy categories, the most common lesion was chronic sialadenitis (N = 7), pleomorphic adenoma (N = 41), and mucoepidermoid carcinoma (MEC) (N = 9), respectively [Table 3].
|Table 3: Spectrum of total salivary gland lesions as per Milan system (N=105)|
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We received 76 tissues (biopsy and specimen) for histopathological examination. In cytohistopathological correlation, concordance was found in 62/76 (81.58%) cases, whereas 8 (10.52%) cases were discordant as benign and 6 (07.90%) cases discordant as malignant [Table 4]. In 02/76 cases, with non-diagnostic smears, one case turned out to be sialadenosis and one case came out as chronic sialadenitis (malignancy risk = 0.0%). Among 10/76 cases of nonneoplastic category, 2 cases were turned to pleomorphic adenoma (malignancy risk = 0.0%); among 2/76 cases of AUS, 1 case was turned out to be pleomorphic adenoma and one case as low-grade MEC (malignancy risk = 50.00%) [Figure 1]a and [Figure 1]b; among 41/76 benign cases, 1 case was came out to be acinic cell carcinoma (malignancy risk = 02.44%) [Figure 1]c and [Figure 1]d. Out of 3/76 cases of SUMP, 2 cases were diagnosed as pleomorphic adenoma and 1 case was diagnosed as basal cell adenocarcinoma (malignancy risk = 33.33%) [Figure 2]a and [Figure 2]b. In SFM category, true malignancy was present in all 3/76 cases (malignancy risk 100%) [Figure 2]c and [Figure 2]d. In the last malignant category, true malignancy was present in 14/76 cases (malignancy risk = 93.33%). In this study, the sensitivity, specificity, PPV, NPV, and diagnostic accuracy of FNAC in diagnosing salivary gland lesions using Milan system was found to be 85.00%, 98.14%, 94.44%, 94.64%, and 94.59%, respectively.
|Table 4: Cytohistological correlation between Milan and histological diagnosis (N=103)|
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|Figure 1:(a and b) Case of atypia of undetermined significance with abundant mucin/myxoid material (Giemsa, ×100) showing features of low-grade mucoepidermoid carcinoma in histology (H and E, ×100) and (c and d) cytomorphology of Warthin tumor showing clusters of oxyphilic cells and scattered lymphocytes (Giemsa, ×100) and histopathology of same case shows features of acinic cell carcinoma (H and E, ×100)|
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|Figure 2: (a and b) Case of uncertain malignant potential shows fragments of monomorphic cells entrapped in hyaline material (Giemsa, ×100), histopathology of same case shows features of basal cell adenocarcinoma (H and E, ×40), and (c and d) case of suspicious for malignancy diagnosed (Giemsa × 400) as adenoid cystic carcinoma with cribriform pattern on histopathology (H and E, ×40)|
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| Discussion|| |
The FNAC was introduced in 1920s, and due to its easy performance and rapidity in diagnosis, it gathered wide acceptance among clinicians. Its important role is to know the origin of lesion, type of pathology, and nature of disease, either benign or malignant, that helps in definite management plan, and it was developed in Europe in 1950 by Antoine Zajdela.
In this study, male (N = 73; 69.52%) were the commonly affected as compared with female (N = 32; 30.48%) with the male:female ratio of 2.2:1. which almost comparative with the few studies., In our study, parotid gland (59.05%) was the common gland to be affected followed in decreasing order of frequency by submandibular glands (31.43%) and minor salivary glands (9.52%). Similar findings were recorded in studies conducted by Sonal and Jain et al.,
In much previous literature, lesions of salivary gland were divided into many formats. A five-group approach system was contrived by Miller's including: (1) myxoid-hyalin, (2) basaloid, (3) oncocytoid, (4) lymphoid, and (5) squamoid lesions. Tessy et al. classified as inflammatory, benign, malignant tumors, and others., Some author's did study under the three groups including nonneoplastic lesions, benign, and malignant tumors. During the reporting of salivary glands lesions, there are lots of confusions like: difficulty in category-wise distribution, particular type of lesion, issue regarding descriptive reports (no categories), and surgical pathology nomenclature. So, Milan system for reporting salivary gland cytopathology (MSRSGC) was organized by the ASC and the IAC in 2017, including six broad categories. The target was to nurture better conveying between clinicians and institutions in order to make better patient care.
In this study, the percentage of nondiagnostic is 2.08%, Nonneoplastic is 16.20%, and neoplastic is 57.14%, that is, quite similar to the study of Rohilla et al. in which the percentage were 2.2%, 55.8%, and 40.4%, respectively.
In our study, maximum number of cases were seen in category IV (neoplastic; benign), followed by category II (nonneoplastic), and VI (malignancy), which correlates well with the studies conducted by Subrata et al., Sheetal et al., and Yogambal et al.,,
In nonneoplastic, benign, and malignancy category, the most common lesions were chronic sialadenitis (41.17%; 07/17), pleomorphic adenoma (75.92%; 41/54), and MEC (52.95%; 09/17), respectively, as mentioned in [Table 3]. Predominance of these lesions was corroborated with the previously reported number of studies.,
In addition, for a salivary gland mass, prior to FNA ROM depends upon the size and location of the lesions: 20%–25% in the parotid gland, 40%–50% in the submandibular gland, and 50%–81% in the sublingual and minor salivary glands.
On follow-up histopathology, recent study presents the overall ROM for different categories that demonstrated almost similarities to the actual ROM of the MSRSGC. But, in some literatures, there were some significant deviations present in AUS and SUMP.,,,, [Table 5] Among the various nonmalignant categories was highest in category III (AUS) followed by categories IVb (SUMP) and IVa (Benign) comparative with the study of Rohilla et al. The category AUS is reserved for specimens that contained limited atypia and a neoplastic process cannot be excluded. The cases diagnosed as AUS is anticipated <10% of all salivary gland FNAs. Higher rates likely represent overuse of this category when other interpretations are more appropriate. The recommended management is a repeat FNA and surgery. In our study, 02.85% (ROM = 50%) of the cases belong to this category and various studies in the literature showed the wide range (0%-73.08%) of ROM for the AUS category. This variation depends upon the subjective error and number of cases and we agree that the fewer number of histopathologically proven cases could have affected the ROM in the current study. So, there is indigence to polished exact defining criteria for this category.
|Table 5: Details of risk of malignancy and comparison with Milan System for Reporting Salivary Gland Cytopathology and other studies|
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Esther et al., 2018 give rise an update on the Milan Classification System for Salivary Gland Tumors with the aim to provide a practical, uniform reporting system linked with risks of malignancy, emphasis on the differential diagnosis, diagnostic problems, and pitfalls according to the new Milan system for reporting salivary gland cytopathology.
Sensitivity and specificity establish various ranges which depend upon the experience of operator performing the FNAC, quality of the cytology preparations, experience of the evaluating cytopathologist, morphological heterogeneity of the lesion, and presence of a cystic component. Overall sensitivity, specificity, and diagnostic accuracy of salivary gland FNA in most series ranges from 86% to 100%, 90% to 100%, and 48% to 94%, respectively.
To the best of our knowledge, there is only one literature searched, describing the sensitivity, specificity, and diagnostic accuracy, but no literature was found to describe the PPV and NPV of salivary gland lesions based on Milan nomenclature. In our study, the overall sensitivity, specificity, and diagnostic accuracy were 85.00%, 98.14%, and 94.59%, respectively, indicating good results as compared with the study done by Rohilla et al.[Table 6].
|Table 6: Comparison of statistical data of present study with other study|
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| Conclusion|| |
This study was undertaken to classify the salivary gland lesions based on MSRSGC and also the aim of this classification system may be much better for reporting salivary gland as each diagnostic category conveys specific risks of malignancy, which provide data that would help in planning the therapeutic approach in patients. MSRSGC facilitates more consistent and uniform reporting of salivary gland FNAs. The overall rate of histological proven malignancy and/or diagnostic accuracy, implementing MSRSGC, may result in lower nondiagnostic rate, less descriptive or implicit interpretation, decreased rate of surgical followup for benign and AUS category, and a reduction of histology-confirmed malignancy in benign category.
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Conflicts of interest
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Department of Pathology, LLRM Medical College, Meerut, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]