Grandhi, Rao, Rao, and Sunandha: Milan scoring system in the diagnosis of salivary gland lesions for assessment of risk of malignancy


Introduction

Fine needle aspiration cytology is a minimally invasive procedure that has been widely accepted in the evaluation of lesions in thyroid, lymph nodes and salivary gland, to name a few. 1, 2 Salivary gland aspiration cytology provides a cost-effective means for their evaluation as it is a very simple and effective. This procedure has avoided unnecessary surgical interventions by differentiating benign from malignant lesions. The sensitivity and specificity of aspiration cytology ranges from 90-100%.3, 4

Salivary gland lesions are known for their diversity and the heterogenecity of the morphological features and thereby many challenges are thrown to the pathologist in the process of final diagnosis. The important aspect is the differentiation of benign from malignant one.5, 6

FNAC has many diagnostic challenge because of the presence of histological features like basaloid pattern of the cells, cystic change, oncocytic and squamous metaplasia. 7 Subclassification of the lesion into benign, suspicious of malignancy or definitive malignancy was done in various studies thus stratifying the risk of malignancy.3 The risk varies from study to study ranging from 6 to 100% and lacks a consensus approach.8

Salivary gland reporting system lacks terminology and various systems have been in use from two tiered to six tiered system. The “Milan System for Reporting Salivary Gland Cytopathology” (MSRSGC), a tiered international classification scheme was proposed by the American Society of Cytopathology and International Academy of Cytology recently. This system (Table 1) provides a guide for clinical management depending on the risk of malignancy (ROM).9, 10

Table 1

The milan system for reporting salivary gland cytopathology (MSRSGC): Implied risk of malignancy and recommended clinical management

Diagnostic category

Risk of malignancy (%)

Management

I

Non-diagnostic

25

Clinical and radiologic correlation/ repeat FNAC

II

Non-neoplastic

10

Clinical follow-up and radiological correlation

III

Atypia of undetermined significance (AUS)

20

Repeat FNAC or surgery

IV

Neoplasm

Neoplasm: Benign

<5

Surgery or clinical follow-up

Neoplasm: Salivary gland neoplasm of uncertain malignant potential (SUMP)

35

Surgery

V

Suspicious for malignancy (SM)

60

Surgery

VI

Malignant

90

Surgery

The current study was done to diagnose and classify the salivary gland lesions by the recent Milan system for assessment of the risk of malignancy.

Materials and Methods

All the cases referred to the department of Pathology from the Department of Surgery, ENT and Dental Surgery for evaluation of salivary gland lesions were included in the study. Clinical data and radiological assessment was done in all these cases. Fine needle aspiration was done. The slides were stained with H and E, PAP stain was used in cases where required. All the cases were reported by a single pathologist to avoid reporting bias and stratified into various categories according to MSRSGC.

Category 1: Non-diagnostic (ND)

Category 2: Non-neoplastic (NN)

Category 3: Atypia of undetermined significance (AUS)

Category 4a: Neoplasm: Benign (NB)

Category 4b: Neoplasm: Salivary gland neoplasm of uncertain malignant potential (SUMP)

Category 5: Suspicious of malignancy (SM)

Category 6: Malignant (M).

Only 105 cases came for follow up, for which histopathological examination was done. Risk of malignancy was thus calculated depending upon the histopathological features.

Results

In our study we had male predominance and most of the cases were seen in the age group of 21-40years.

Table 2

Distribution of cases according to age, sex, and site of involvement Sex distribution of the lesions

Sex

No. of cases

%

Males

118

51.5

Females

107

48.5

Total

225

100

Table 3

Age distribution of the lesions

Age group

No. of cases

%

0-20

31

13.6

21-40

104

46.1

41-60

61

27

61-80

22

10.2

>81

7

3

Total

100

Patients had presented with lesions in all the major and minor salivary glands-parotid, submandibular and sublingual. Majority of the cases were seen in the parotid gland.(57.7%).

Table 4

Site distribution of the lesions

Site

No. of cases

%

Parotid

130

57.7

Submandibular

61

27.3

Sublingual

34

15

Total

100

Table 5

Age distribution of the lesions

Age group

No. of cases

%

0-20

3

3.61

20-40

22

26.50

40-60

39

46.98

60-80

19

22.89

Cytological evaluation was done according to the Milan system as shown in Table 6.

Table 6

Histological follow-up of Milan system diagnostic categories

Category

Cat 1

Cat 2

Cat 3

Cat 4a

Cat 4b

Cat 5

Cat 6

Total

No. of cases

15 (6.1%)

90 (38.2%)

04 (2.7%)

72 (33.4%)

04 (2.0%)

06 (2.4%)

34(15%)

225

No. of cases with histological follow-up

06 (2.3%)

40 (11.6%)

04 (2.9%)

35 (52.3%)

02 (3.5%)

03 (4.1%)

15 (23.2%)

105 (58.7%)

Benign: non-neoplastic

4 (50%)

28 (65%)

-

03 (1.1%)

01 (16.6%)

-

2

37 (9.8%)

Benign: neoplastic

01 (25%)

10 (30%)

03 (80%)

32 (94.4%)

0

0

-

46 (58.7%)

Malignant

01 (25%)

02(5%)

01 (20%)

01 (4.4%)

1 (33.3%)

3 (85.7%)

13(97.5%)

23 (31.4%)

Risk of malignancy

01/04 (25%)

02/40 (5%)

01/04 (25%)

1/35(2.8%)

01/2 (50%)

3/3 (100%)

13/5 (86.6%)

23/105 (21.9%)

[i] Non neoplastic category was the most common(40%) followed by neoplastic, benign (32%)

Discussion

FNAC is a safe, accurate, and cost-effective method for evaluation of salivary gland swelling and can help in management of the patient by avoiding unnecessary surgery in cases where there no malignancy as is assessed by the risk of malignany given by Milan system of scoring.11, 12, 13

The patient management is made easy by MSRSGC, a new system used for reporting salivary gland lesions with risk stratification. As discussed previously it is a evidence based six tiered system, providing risk of malignancy which is very useful for the treatment of the patients.11, 12, 13 The six categories as per this system are Non diagnostic(ND), Non neoplastic(N), Atypia of undetermined malignancy(AUS), Neoplasm-Benign (NB),Neoplasm-Suspicious of malignant potential(SUMP), Suspicious of malignancy(SM), and Malignant. Risk of malignancy(ROM) as given by this system is as follows: 25%, 10%, 20%, 5%, 35%, 60%, and 90% for each category.9 In our study after categorising the various lesions, we have assessed the risk of malignancy. ROM for the various categories is as follows: 25% for category I-Non diagnostic, 5%, for category II-Non neoplastic, 25% for category III-Atypia of undetermined significance,2.8% for category IV a – Neoplasm: Benign, 50%-IV b- Neoplasm:Salivary gland neoplasm of uncertain malignant potential, 100% for category V- Suspicious of malignancy and lastly 86.8% for category VI- Malignant. These results are comparable to those given in the Milan system.

We now discuss each category in detail with reference to the cytological and morphological features.

In the Category 1, in view of insufficient material for diagnosis, they are non-diagnostic so cannot give an informative interpretation. There were 6 cases (3.3%) in our study belonging to this category(ND). Histopathological follow-up revealed 4 cases to be chronic sialadenitis. 1 case was Pleomorphic adenoma, which in view of secondary changes, yielded an insufficient aspirate on fine needle aspiration.1 case was diagnosed as Adenocarcinoma with marked cystic change on histology that lead to insufficient aspiration on cytology.

Now we shall discuss the Category 2, non neoplastic. Only 40(44%) out of 90 cases came for follow up. Most of the cases have good cytomorphological co relation except for 1 case. This case was actually diagnosed as acute sialadenitis,but on histopathological examination, it was diagnosed as carcinoma-ex pleomorphic adenoma, the areas of necrosis seen in histopathology were actually mis interpreted as inflammatory debris and diagnosed as acute sialadenitis in cytology.

Under the next category, Atypia of undetermined significance, all the 4 cases came for follow up(100%). This category is a grey zone as malignancy cannot be ruled out. 3 cases were pleomorphic adenoma with mild atypia on histopathology. These atypicals cells were the reason for diagnosing as AUS on cytology. One case was Adenoid cystic carcinoma, the cells which seen as dispersed cells with atypia are the cells of adenoid cystic carcinoma with a different pattern(solid) mis diagnosed as atypia in cytology.

The 4th category has 4a and 4b.35 cases out of 72 have come for follow up. The most common benign lesion was Pleomorphic adenoma the maximum co relation was seen in this category. Only 1 case which was diagnosed as pleomorphic adenoma turned out to be carcinoma adenoid cystic carcinoma. The various patterns i.e. solid, trabecular and cribriform pattern were misinterpretated as epithelial and mypepithelial componnets in cytology and was underdiagnosed as Neoplasm Benign, possibility of Pleomorphic adenoma.

In cases where cytology is not able to differentiate between benign and malignancy we label it as suspicious of malignant potential.2 out 4 cases (50%) came for follow up. 1 case was non neoplastic on histology. The other was malignant, adenocarcinoma. Thus one case was over diagnosed as suspicious of nmalignacy in view of marked atypia which was actullay due to acute inflammatory process.

The 5th category, suspicious for malignancy is a entity for cases where the features are suggestive. All the 3 cases came for follow up were diagnosed as Adenoid cystic carcinoma giving rise to 100% efficacy between cytology and histopathology.

The last category included malignant. Here the features are very much diagnostic. 15 cases came for follow up. 13 cases were malignant on histopathology with ROM being 86.6%.1 case was pleomorphic adenoma which was signed out as malignant in cytology and other case was sialadenitis with severe atypia which again was diagnosed as malignant in cytology.

As we have limited studies in this field of cytology we would conclude that further research has to be done. The other limitation of our study is sample size.

Source of Funding

None.

Conflict of Interest

The authors declare no conflict of interest.

References

1 

G Colella R Cannavale F Flamminio M P Foschini Fine-needle aspiration cytology of salivary gland lesions: A systematic reviewJ Oral MaxillofacSurg201068214653

2 

R Jain R Gupta M Kudesia S Singh Fine needle aspiration cytology in diagnosis of salivary gland lesions: A study with histologic comparisonCytojournal2013105

3 

S Schindler R Nayar J Dutra C W Bedrossian Diagnostic challenges in aspiration cytology of the salivary glandsSeminDiagnPathol200118124170

4 

S Chakrabarti M Bera P K Bhattacharya D Chakrabarty A K Manna S Pathak Study of salivary gland lesions with fine needle aspiration cytology and histopathology along with immunohistochemistryJ Indian Med Assoc2010108833839

5 

S Ahn Y Kim Y L Oh Fine needle aspiration cytology of benign salivary gland tumors with myoepithelial cell participation: An institutional experience of 575 casesActaCytol20135756774

6 

J H Hughes E E Volk Dc Cytopathology Resource Wilbur Committee College of American Pathologists. Pitfalls in salivary gland fine-needle aspiration cytology: Lessons from the College of American Pathologists Interlaboratory Comparison Program in Nongynecologic CytologyArch Pathos Lab Med20051292631

7 

C C Griffith R K Pai F Schneider U Duvvuri R L Ferris J T Johnson Salivary gland tumor fine needle aspiration cytology: A proposal for a risk stratification classificationAm J ClinPathol201514383953

8 

A Malik Z Maleki H Q Zhao E D Rossi P Bo A Chandra Inter-institutional variability of “atypical” salivary gland fine needle aspiration: A multi-institutional studyLab Invest201797107107

9 

Faquin WC Rossi ED The Milan System for Reporting Salivary Gland CytopathologySpringer2018

10 

ED Rossi WC Faquin Z Baloch GA Barkan MP Foschini M Pusztaszeri The Milan system for reporting salivary gland cytopathology: Analysis and suggestions of initial surveyCancer Cytopathol201712575766

11 

P Mairembam A Jay T Beale S Morley F Vaz N Kalavrezos Salivary gland FNA cytology: Role as a triage tool and an approach to pitfalls in cytomorphologyCytopathology201627916

12 

BY Kim J Hyeon G Ryu N Choi CH Baek YH Ko Diagnostic accuracy of fine needle aspiration cytology for high-grade salivary gland tumorsAnn Surg Oncol20132023807

13 

A Pastore M Borin N Malagutti A Di Laora D Beccati AL Delazer Preoperative assessment of salivary gland neoplasms with fine needle aspiration cytology and echography: A retrospective analysis of 357 casesInt J Immunopathol Pharmacol20132696571



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Article History

Received : 04-10-2021

Accepted : 09-10-2021

Available online : 23-11-2021


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https://doi.org/10.18231/j.ijpo.2021.092


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