Pleomorphic Adenoma : Secondary Changes
Prior manipulation or fine needle aspiration (FNA) can cause secondary changes in pleomorphic adenomas. They include hemorrhage, pseudo-invasion, calcification, cholesterol granuloma formation, squamous metaplasia, necrosis and infarction. In the absence of prior history of surgical manipulation, necrosis and infarction should lead to suspicion for malignant transformation. This image shows a large area of infarction induced by FNA. A thin rim of viable pleomorphic adenoma can be seen on the right side.