Salivary gland lesions comprise less than 1% of all tumors and 4% of all epithelial neoplasm in head and neck. They are broadly classified as neoplastic and non-neoplastic. Clinically they may present as tumor and may have pathological features similar to some of neoplasm. Fine needle aspiration cytology (FNAC) is a cyto-diagnostic method based on morphologic findings of individual and small group of cells aspirated using a fine needle. The role of FNAC in suspected salivary gland swellings is to confirm its origin and to get a preliminary diagnosis about the nature of the disease process before the definite management plan. FNAC is a reliable method to differentiate between inflammatory and neoplastic lesions. FNAC diagnosis of neoplastic lesions process even when benign usually leads to Surgical excision. The aim of the present study is to evaluate the spectrum of salivary gland lesions in our setting and to assess the diagnostic accuracy of FNAC for salivary gland lesions.

AIMS AND OBJECTIVES

To evaluate role and utility of FNAC in diagnosis of salivary gland lesions. To evaluate benign and malignant salivary gland lesions and study age, sex and site wise distribution of salivary gland lesions.

METHODS & MATERIAL

This is a retrospective observational study performed in Cytopathology laboratory, Department of Pathology, PDU Medical college & Hospital, Rajkot of 3 years during the period of January 2022 to December 2024. The study involved 150 cases who presented with parotid, submandibular & minor salivary gland swellings. FNAC was performed using a 22–23gauge needle attached to a disposable syringe with plunger under aseptic conditions. Smears were prepared and slides were stained with haematoxylin and eosin and Giemsa methods. The results of FNAC and final histopathology were compared wherever was possible and accuracy of FNAC was determined.

Inclusion Criteria: All smears with enough aspirated material.

Exclusion Criteria: Smears having inadequate material and inconclusive diagnosis.

Results: A total of 150 cases were analysed retrospectively within the period of three years from January 2022 to December 2024. Out of these 150 cases, 51(34%) were diagnosed as non-neoplastic lesions and 99(66%) as neoplastic lesions. (Table 1)

Table 1: Distribution of non-neoplastic and neoplastic salivary gland lesions.

Chronic & Acute Sialadenitis 38(25.3%) were the most common non neoplastic lesion in our study followed by Mucocele of salivary glands which accounts for 13(8.67%) of all the salivary lesions. Amongst neoplastic lesions 99(66%), Benign lesions 90(60%) outnumbered malignant lesions 9(6%). Pleomorphic adenoma 64 (42.67%) was most common benign lesion, followed by Warthin’s tumour 25(16.67%) and basal cell adenoma 01(0.67%) was least common. Mucoepidermoid carcinoma 4(2.67%) was most common malignant lesion of salivary gland. (Table 2)

Table 2: Distribution of various salivary gland lesions.

In the study it was observed that the commonest site of salivary gland lesion was parotid gland 94(62.7%), followed by submandibular gland 42(28%) and 14(9.3%) of minor salivary glands. (Table 3)

Table 3: Site wise distribution of salivary lesions

Males were more affected more than females (M:F ratio 1.67:1) overall. Female predominance was there in case of pleomorphic adenoma (M:F ratio 0.86:1). In all other cases male predominance was observed. (Table 4).

Table 4: M:F ratio of different salivary gland lesions.

Overall, most commonly affected age group was 20 to 30 years of age 27(18%). (Chart 1).

Chart 1: Age distribution of salivary gland lesions

In male most common affected age group was 50 to 60 years of age 19(12.67%). Among female, 2^nd & 3^rd decade was most commonly affected (11 & 11 respectively (7.33%). (Chart 2)

Chart 2: Age distribution of salivary lesions in male & female.

Among non-neoplastic lesions, acute & chronic sialadenitis was more common in 2^nd decade of life in male 8(5.33%) & 3^rd decade in female 4(2.66%) respectively. Benign neoplastic lesion, Pleomorphic adenoma was more common in 3^rd decade in male 8(5.33%) and 2^nd decade in female 7(4.67%). Warthin’s tumour was found to be common in 5^th decade of life in male 10(6.66%), wasn’t recorded in females in our study.

Malignant tumour, Mucoepidermoid carcinoma was found in equal proportions in male & female in variable age group. Carcinoma Ex Pleomorphic Adenoma was 2^nd most common malignant lesion, was common in 4^th and 5^th decade in males and was found in female of >80 years of age in our study. (Table 5 & 6)

Table 5: Distribution of salivary lesions in different age group in male.

Table 6: Distribution of salivary lesions in different age group in female.

Acute and chronic sialadenitis show predominantly inflammatory cells (polymorphs and lymphocytes respectively) and fragments of ductal epithelial cells with few/ absent acinar cells along with fibrotic stroma. (Figure 1: (a) & (b).

Figure 1: (a)&(b)Cytomorphology of chronic sialadenitis showing fragments of ductal epithelial cells, at places, few acinar cells seen. Background shows chronic inflammatory cells mainly lymphocytes.

Mucinous cyst/Mucocele of salivary gland show presence of thick mucinous material with ductal or acinar cells showing secretory granules or vacuoles.

Figure 2: Mucinous cyst/Mucocele of salivary gland show presence of thick mucinous material with ductal or acinar cells showing secretory granules or vacuoles.

Pleomorphic Adenoma is a matrix containing tumour having unique fibrillary stroma, mixture of myoepithelial cells which are round to polygonal plasmacytoid spindle cells, ductal cells with honeycomb or ductal arrangement and extracellular stroma with characteristic feathery/ fibrillary borders and chondromyxoid features.

Figure 3: (a)&(b)Cytomorphology of pleomorphic adenoma showing epithelial cells with ovoid myoepithelial cells and chondromyxoid stroma (H & E).

Warthin’s Tumour show small cohesive sheets of oncocytes with abundant granular cytoplasm, central round nucleus with prominent nucleolus and many lymphocytes with granular debris in background.

Figure 4: (a)&(b)Cytomorphology of warthins’ tumor showing sheets of oncocytic cells, polymorphs, population of lymphocytes in dirty granular background.

Basal cell adenoma shows monomorphic basaloid cells with round nuclei and scanty cytoplasm with irregular nests and trabecula, tubular or peripheral palisading architecture. Few cases may show chondromyxoid stroma and myoepithelial cells or cytological atypia, mitosis and necrosis.

Figure 5: (a)&(b)Cytomorphology of basal cell adenoma show monomorphic basaloid cells with smooth borders, round nuclei, irregular nests, trabecula and scanty cytoplasm.

Carcinoma Ex Pleomorphic adenoma has two components as the name suggests – Pleomorphic Adenoma component showing sheets or cohesive groups of ductal cells, myoepithelial cells dispersed or in loose clusters, dense fibrillary metachromatic matrix and Carcinomatous component- Pleomorphic, hyperchromatic cells, clumped chromatin, high N:C ratio, necrotic background. Mucous or squamous cells may be seen.

Figure 6: (a)&(b)Cytomorphology of carcinoma ex pleomorphic adenoma shows small clusters, sheets and many dispersed neoplastic cells hyperchromatic angulated nuclei and dense eosinophilic cytoplasm.

Mucoepidermoid carcinoma is composed of a variable mixture of squamous cells, mucus secreting and intermediate cells occasionally focal sebaceous gland, goblet cells also seen. They are the most common form of primary malignant tumour of the salivary glands. In the present study, among malignant cases diagnosed by FNAC, mucoepidermoid carcinoma was present in 4(2.67%) cases and was the most common primary malignancy. Discordant diagnoses between cytology and histopathology is common, which occurs due to multiple factors. Cytology details should be carefully examined for scanty cytoplasm, high nucleus to cytoplasmic ratio, naked nuclei, nuclear moulding, and hyperchromasia to avoid erroneous diagnosis among the non-neoplastic lesions. On cytological examination, discordant pleomorphic adenoma was common, which on histopathological examination was diagnosed as carcinoma ex pleomorphic adenoma. Pleomorphic adenoma can be misdiagnosed as mucoepidermoid carcinoma on cytological examination because aspiration of mucoid paucicellular fluid may suggest low grade mucoepidermoid carcinoma.

Figure 7: (a)&(b)Cytomorphology of Mucoepidermoid carcinoma showing small clusters, sheets and many dispersed neoplastic cells hyperchromatic angulated and overlapping nuclei and dense eosinophilic cytoplasm.

Adenoid cystic carcinoma a primary salivary gland lesion characterized by its biphasic ductal and myoepithelial differentiation. Cytomorphology shows metachromatic matrix spheres with sharply defined border called Hyaline globules surrounding cohesive clusters of basaloid cells with scant cytoplasm, angulated hyperchromatic nuclei and indistinct nucleoli.

Figure 8: (a)&(b)Cytomorphology of adenoid cystic carcinoma - cellular smears with metachromatic matrix spheres with sharply defined border called Hyaline globules surrounding cohesive clusters of basaloid cells with scant cytoplasm, angulated hyperchromatic nuclei and indistinct nucleoli.

The cytologic diagnosis was later correlated with histopathological diagnosis [Table 7]. Out of the total of 150 cases, histological correlation was established for 131(87.3%). Histopathological correlation was not established for 11(7.3%) cases and no correlation data was available for 8(5.3%) cases. In our set up cytopathology was histopathologically confirmed on an average up to 85% in case various salivary lesions.

Table 7: Cytopathological & Histopathological Correlation

DISCUSSION

Out of the total of 150 cases studied by us, non-neoplastic lesions were 51(34%) and neoplastic lesions were 99(66%), which is similar to studies done by Shivani Gupta et al . (Table 8).

Table 8: Comparision with other studies of incidence of Benign & Malignant lesions.

Benign lesions predominated over malignant lesions among all neoplastic lesions which was similar to the study of Desai P et al and Junudevi et al. (Table 8)

The most commonly affected among the salivary glands was parotid gland followed by submandibular gland which was similar to other studies. (Table 9)

Table 9: Site distribution of salivary gland lesions in different studies.

Age distribution: Non neoplastic lesions were common in 2^nd decade of life in our study. Neoplastic benign lesions were common in 3^rd and 4^th decade which was correlated with the study of Rajdeo RN et al and Desai P et al. Neoplastic malignant lesions were found to be common in between 40 – 60 years of age similar to the study of Rajdeo RN et al.

Gender distribution: Though salivary lesions are found to be more common in females, in our study there was male predominance over female with M:F ratio being 1.67:1 which was similar to the study of Ganguly et al. The probable reason could be lack of awareness and ignorance amongst the women about healthcare and the prevalence of tobacco addiction in males in our region.

Table 10: Male: Female ratio in benign and malignant lesions in various studies.

In our study the cytopathological diagnosis was later confirmed by histopathological evaluation making a diagnostic accuracy in 122(81.33%) cases. Different studies show variable degrees of cytopathological correlation with histopathological diagnosis. (Table 11)

CONCLUSION

FNAC is an excellent preliminary diagnostic technique for the diagnosis of salivary gland swelling. However, it may be challenging sometimes especially when cytological features overlap.

Therefore, it is mandatory to use FNAC for primary investigation and it should always be done in conjunction with histopathology along with patient clinical history, physical examination and ultrasonography to reach the correct diagnosis. The present study shows salivary gland lesions are wide range of lesions from non-neoplastic to neoplastic lesion. Benign lesions are more common than malignant lesions with parotid gland being the most common site and pleomorphic adenoma, the most common tumor type. Mucoepidermoid carcinoma is the most malignant primary tumor. Most common age group affected is 51-60 years. Among tumors, female preponderance is seen in pleomorphic adenoma and male predominance in Warthin tumor. So, thorough knowledge of morphology of salivary gland lesion is helpful in final diagnosis in predicting prognosis, typing, staging and grading of salivary neoplasms.

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