Capsular penetration and perforation in pleomorphic adenoma of the parotid salivary gland.

Both penetration and perforation of the capsule were seen on the superficial aspect of pleomorphic adenomas. Only penetration was noted on the deep aspect, where the tumour was adjacent to the facial nerve. In terms of local recurrence this may explain why it appears to be safe to separate the deep aspect of the tumour from the facial nerve without a wide margin of normal parotid tissue.