Primary Pleomorphic Lipoma of the Parotid Gland with Prominent Myxoid Change: Report of a Rare Case Mimicking Carcinoma Ex Pleomorphic Adenoma on Fine Needle Aspiration Cytology.

We present a case of a primary 2.5 cm pleomorphic lipoma of the right parotid gland with prominent myxoid change which on FNA displayed features that mimicked a carcinoma or sarcoma ex pleomorphic adenoma. The patient was a 79 year old man with no oncological history or tumor elsewhere. On immunohistochemistry the neoplastic cells strongly expressed CD34. There was no expression of retinoblastoma protein, smooth muscle actin, S100-protein or cytokeratins (AE1/3 and CAM5.2). The Ki-67 proliferation index was low (< 2%). Fluorescence in situ hybridization was negative for MDM2 gene amplification.