Advanced magnetic resonance imaging findings in salivary gland tumors

Table 1 Evaluation on advance magnetic resonance imaging techniques of salivary gland tumors

	Advance magnetic resonance imaging techniques
	Lymphoma	Warthin’s tumor	Malign tumor	Pleomorphic adenoma
Diffusion weighted ımaging (ADC values)	< 0.8 × 10-3 mm2/s	(0.8-1.0) × 10-3 mm2/s	(1.0-1.2) × 10-3 mm2/s	> 1.2 × 10-3 mm2/s
Dynamic contrast-enhanced MRI	50 s < Tpeak < 90 s, WR < 30%	Tpeak < 50 s, WR ≥ 30%	Tpeak < 120 s, WR < 30%	Tpeak > 120 s, WR: Non-washout
Quantitative dynamic contrast-enhanced perfusion MRI		Ktrans < 0.8 min−1, Kep > 1 min−1, Ve < 0.2	Ktrans < 0.5 min−1, Kep < 1 min−1, Ve > 0.3	Ktrans < 0.3 min−1, Kep < 0.6 min−1, Ve < 0.9

ADC: Apparent diffusion coefficient; MRI: Magnetic resonance imaging; Tpeak: Time to peak; WR: Wash-out ratio; Ktrans: Volume transfer constant between blood plasma and extracellular extravascular space; Kep: Flux rate constant between the extracellular extravascular space and plasma; Ve: Extracellular extravascular space fractional volume.

Table 2 World Health Organization classification of salivary gland tumors 2017

Salivary gland tumors
Malignant tumors	Benign tumors
Mucoepidermold carcinoma	Pleomorphic adenoma
Adenoid cystic carcinoma	Myoepithelioma
Acinic cell carcinoma	Basal cell adenoma
Polymorphous adenocarcinoma	Warthin’s tumor
Clear cell carcinoma	Oncocytoma
Basal cell adenocarcinoma	Lymphadenoma
Intraductal carcinoma	Cystadenoma
Adenocarcinoma, NOS	Sialadenoma papilliferum
Salivary duct carcinoma	Ductal papillomas
Myoepithelial carcinoma	Sebaceous adenoma
Epithelial-myoepithelial carcinoma	Canalicular adenoma and other ductal adenomas
Carcinoma ex pleomorphic adenoma	Non-neoplastic epithelial lesions
Secretory carcinoma	Sclerosing polycystic adenosis
Sebaceous adenocarcinoma	Nodular oncocytic hyperplasia
Carcinosarcoma	Lymphoepithelial sialadenitis
Poorly differentiated carcinoma	Haemangioma
Lymphoepithelial carcinoma	Lipoma/sialolipoma
Squamous cell carcinoma	Nodular fasciitis
Oncocytic carcinoma	Haematolymphoid tumors
Sialoblastoma	Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue

NOS: Not otherwise specified.