Salivary gland neoplasms: Histomorphological assessment of an enigmatic group of tumours

Abstract

Introduction: Salivary gland tumours are complex and exhibit varied clinico-pathological features.These tumours are particularly important to the otolaryngologists, head and neck surgeons and oncologists because of their associated morbidity and mortality. Material and methods: The archives of department of histopathology were retrospectively reviewed from January 2011 to January 2016. All cases of salivary gland neoplasms were included in
this study. Clinical details were obtained from the medical records. Diagnosis was confirmed on hematoxylin and eosin (H&E) stained formalin fixed paraffin embedded sections from excised specimens. Results: 235 patients with salivary gland tumours were included in the study. The mean patient age at the time of presentation was 45.5 years (range 17-79 years). There were 90 males and 145 females with a male: female ratio of 1:1.6. Parotid gland was most commonly involved (76%) followed by the submandibular gland (22%) and minor salivary glands (2%) Benign tumours (74.4%) exceeded malignant tumours of salivary glands (25.6%). The most common benign salivary gland neoplasm was pleomorphic adenoma (155 cases), followed by 10 cases of Warthin’s tumour, 5 cases of basal cell adenoma, 2 cases of myoepithelioma and schwannoma each and a single case of oncocytoma. Adenoid cystic carcinoma was the most frequently reported malignant tumour of the salivary glands (29 cases), followed by 19 cases of muco- epidermoid carcinoma, 2 cases of salivary duct carcinoma, 3 cases each of carcinoma-ex pleomorphic adenoma, and a single case each of acinic cell carcinoma, carcinosarcoma, osteosarcoma and giant cell tumour of salivary gland. Conclusion: Benign tumours are more common than malignant tumours in the salivary glands. Histomorphological assessment is imperative prior to therapeutic intervention. Unusual entities like nerve sheath tumour, osteosarcoma, carcinosarcoma and giant cell tumour must be kept in mind as a differential diagnosis by the clinicians and pathologists.