Open biopsy is done for salivary gland tumor unless they are arising from:-

Open surgical biopsy is contraindicated in parotid tumors because it can cause tumor seeding of the track and increased risk of parotid fistula formation. The initial imaging modality of choice is ultrasound as it demonstrates if the lump is intrinsic to the parotid or not. It also facilitates accurate sampling of the lesion by FNAC or True-Cut biopsy. Subsequently, CT and MRI are the most useful imaging techniques. Open surgical biopsy is contraindicated unless evidence of gross malignancy is present, and preoperative histological diagnosis is required as a prelude to radical parotidectomy.