Benign and Malignant Tumors of Parotid Gland: A Retrospective Two Year Study

Abstract

Introduction: Parotid tumors affect 1in100,000 people, representing 2-3%of tumors of the head and neck and 80% of salivary gland tumors. The literature estimates that approximately 80% of these tumors are benign, with pleomorphic adenoma being the most common followed by Warthin’s tumor.\xa0 Among the malignant tumors mucoepidermoid carcinoma is the commonest, followed by adenoid cystic carcinoma. \nMaterial methods: It was a retrospective study done from January 2016 to December 2017 in the department of pathology Government Medical college Srinagar. \nResults: our study included 42 cases of parotid gland tumors. Out of 42 cases 25 were female and 17 were male patients. Thus the male to female ratio observed was 1:1.4.\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Pleomorphic adenoma (twenty cases) was the most frequent benign tumor followed by warthin’s tumor (five cases) while as mucoepidermoid carcinoma was the most frequently identified malignant tumor. \nConclusion : pleomorphic adenoma is the most prevalent benign histological type while as mucoepidermoid carcinoma is commonest malignant tumor. Malignant tumors are more common in 5th decade while as benign lesions are commoner in 4th decade of life. \nKey words:\xa0 pleomorphic adenoma , warthins tumor , mucoepidermoid carcinoma. \nIntroduction: \xa0Tumours of salivary glands are rare constituting less than one percent of all tumors and 3% to 10% of the neoplasms of head and neck region (1). Parotid tumors affect 1in100,000 people, representing 2-3%of tumors of the head and neck and 80% of salivary gland tumors (2). The literature estimates that approximately 80% of these tumors are benign, with pleomorphic adenoma being the most common followed by Warthin’s tumor (3). The parotid gland has a superficial lobe, lateral to the facial nerve, that comprises 4/5 of the glandular parenchyma, and a smaller deep lobe. As 90% of the tumors are located in the superficial lobe and thus, do not affect the facial nerve hence superficial parotidectomy with facial nerve preservation is the most often indicated surgical procedure, (4). \n\xa0\xa0\xa0\xa0 The most common manifestation of pleomorphic adenoma is the presence of a solitary, solid, firm, lobulated, painless, mobile nodular lesion with well-defined margins (5). Among the malignant tumors mucoepidermoid carcinoma is the commonest, followed by adenoid cystic carcinoma. The presence of pain, facial paralysis, rapidly growing tumor with ill-defined margins, and skin infiltration should raise the suspicion of malignancy (4). \n\xa0\xa0 \xa0\xa0The first diagnostic imaging assessment for parotid tumors is usually ultrasonography (5). Fine-needle aspiration cytology (FNAC), whether or not guided by ultrasound, can be used as a complementary diagnostic test, especially when a non-characteristic manifestation of pleomorphic adenoma is suspected. The purpose of FNA is to differentiate benign from malignant lesions, as it usually does not establish the definitive histological diagnosis. However, histopathology remains the gold standard as it avoids diagnostic pitfalls of FNAC (3,4). \xa0 \nMaterial methods: It was a single institute retrospective study done from January 2016 to December 2017 in the department of pathology Government Medical college Srinagar. Clinical data and gross features of tumours were recorded and tabulated. Haematoxylin and eosin (H&E) stained sections and corresponding paraffin tissue blocks were retrieved from the archives of the department and reviewed. The tumors were categorized according to the WHO classification. \nResults: During the period of two years a total of 69 salivary gland surgeries were performed, which included 42 (60.8%) parotidectomies. Thus, our study included only these 42 cases of parotid gland tumors. The demographic analysis is given in (Table.1). Out of 42 cases 25 were female and 17 were male patients. Thus the male to female ratio observed was 1:1.4. At presentation, the main finding was a tumor mass measuring >2cm in size in 73.8% of all cases reported in our study. Superficial lobe of parotid gland was the commonest site involved in \n\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Pleomorphic adenoma (twenty cases) (fig-1) was the most frequent benign tumor followed by warthin’s tumor (fig-2) (five cases) while as mucoepidermoid carcinoma (fig-3) was the most frequently identified malignant tumor (three cases) (Table.2). \n\xa0\xa0 \xa0The most relevant clinical characteristics of the benign and malignant tumors are shown in Table 3.The ratio between men and women for malignant tumors was1:2, while for benign tumors it was 1:1.4. The mean age for the presentation of benign tumors was 46 years and for malignant tumors was 58 years.