Haemangiopericytoma and solitary fibrous tumour of the parotid gland: a scoping review

Salivary gland tumours represent about 3-10% of head and neck tumours, with the parotid gland being the most affected. The World Health Organization classification of these tumours is continually evolving due to their diverse histology and biological behaviour. Haemangiopericytoma (HPC) and solitary fibrous tumour (SFT) have been reclassified as a single entity characterised by NAB2-STAT6 gene rearrangement, typically presenting as slow-growing, painless masses in the parotid region, and immunohistochemistry is essential for diagnosis. This study aims to examine the clinical characteristics of these tumours to better understand their biological behaviour. Following PRISMA 2020 guidelines, we reviewed the literature using the search string (haemangiopericytoma), OR (solitary fibrous tumor) AND (parotid gland). Of the initially collected 201 papers, 49 were selected for detailed analysis, focusing on data from 53 patients, all of whom underwent surgery. Of these patients, 11.3% (n = 6) were diagnosed with malignancy, while 3 more were suspected to have malignancy. Our findings suggest that SFT morphology predominates among lesions, but malignancy is more often associated with features of HPC. Further comprehensive study is needed to gather additional data on their biological behaviour.