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 an area of infarction (left half) and squamous metaplasia (upper right) following FNA.