Sonographic Features of Salivary Gland Tumours

Objective: High resolution ultrasonography (US) has played a significant role in the study of salivary gland (SG) pathology and has surpassed sialography in the study of SG tumours. This report discusses the sonographic features of SG tumours examined during the last 5 years. The value of these features as diagnostic indicators of the nature (benign or malignant) and histotype of these tumours is assessed. Methods: High resolution ultrasonography was used in the study of 83 cases of salivary tumours, 78 of which were of the parotid gland and 5 of the submandibular gland. Sixty-six (80%) of these tumours were benign. An US scanner with a 7.5-MHz real-time linear probe was used. The diseased SG was examined in multiple planes to fully delineate and locate the lesions and to characterize their sonographic features. Results: US detected and correctly located all tumours. The sonographic features of the various tumour categories studied are presented with special emphasis on diagnostically significant ones. The value of these features as diagnostic indicators of the nature (benign or malignant) and the histotype of these tumours is assessed. In this study, the rate of correct US identification of tumour benignity was 100% in a group of 15 adenolymphomas and 12 benign non-epithelial tumours, and 94% in a group of 34 pleomorphic adenomas. Five cases of recurrent pleomorphic adenoma were also studied. Correct US identification of malignancy was achieved in 82% of malignant tumours (15 carcinomas and 2 isolated primary non-Hodgkin’s lymphomas of the parotid gland). US identification of the specific tumour histotype was quite successful in the case of benign tumours with an accuracy of 84% in pleomorphic adenoma, 93% in adenolymphoma, and 100% in vascular tumours and lipoma. Only 1 of the 17 malignant tumours (a carcinomatous pleomorphic adenoma) was specifically identified. Conclusion: Based on the diagnostic capabilities of US revealed in this study as well as its operational advantages, US is strongly recommended as the first-line imaging procedure for all masses at the SG regions, to be followed by US-guided fine needle aspiration biopsy particularly for equivocal cases.