Applying ‘Sal classification’ to parotid cytology to replicate the success of the Thy classification system
Reviewed by Aileen Lambert

The usefulness of the Thy classification in thyroid gland disease has led to attempts to generate a similar cytology classification for parotid lesions. However, the accuracy of fine-needle aspiration cytology in salivary gland disease is more variable because of the overlap in appearance between benign and malignant tumours as well as the relative rarity of these lesions. In 2016 a multicentre UK group (Bajwa et al.) proposed the Sal classification in order to better predict outcomes in salivary gland tumour FNAC, particularly of ‘non-definitive’ cytology. This recent retrospective Turkish study of 312 patients applied the Sal cytology system and proposed some amendments to the original classification. They undertook analysis of the accuracy of the system using a validated Galen and Gambino method (using two scenarios for each borderline suspicious result). The main focus of their sensitivity and specificity results revealed that nondefinitive cytology such as in the Sal 3 category had a considerable malignancy rate (17.3%). As it stands currently they recommend clinical caution and use of additional investigations such as imaging when interpreting these unspecific results. They suggest that further large prospective cytological studies are needed to facilitate refinement of this classification system. 

Application of Sal classification to parotid gland fine-needle aspiration cytology: 10-year retrospective analysis of 312 patients.
Kilavuz AE, Songu M, Imre A, et al.
HEAD & NECK
2018;40:937-42.