"These tumours usually occur in older patients (6th to 8th decade), who have had a pleomorphic adenoma in situ for many years (typically 10-15 years) 1."
Line 5:128·Italics should be used only in exceptional circumstances: '<em>in situ </em>'
Oxford Comma
suggestion
"T1: heterogeneous signal due to haemorrhage, necrosis and calcification 1"
Line 12:57·Use the Oxford comma in 'haemorrhage, necrosis and calcification'.