Pleomorphic adenomas of the major salivary glands: a study of the capsularform in relation to surgical management

This was a retrospective study of 126 primary pleomorphic adenomas to corre late capsular characteristics with tumour histopathology in relation to cur rent surgical debate (parotidectomy versus local excision). Capsular thickn ess was measured by micrometry and tumours classified into subtypes (1-4). Evidence of fine needle aspiration damage (needle tracks, infarction) was s ought. Minimal changes were seen in eight tumours. Tumour growth features ( bosselations, enveloping) were present in 57% and 33%, respectively, also m icroinvasion (42%) and tumour 'buds' (12%). Parotid lesions possessed thick er capsules than submandibular tumours. There was little correlation betwee n capsular thickness and cellular structure. The significant exception was large (> 25 mm) hypocellular parotid tumours which had thinner capsules and could be vulnerable to operative rupture. In 110 standard operations (paro tidectomy, submandibular gland excision), capsular exposure was evident in 81%. Field irrigation is recommended to lessen the risk of tumour seeding. This study reaffirms many elements of capsular weakness and suggests that p arotidectomy is the operation of choice.