Unusual metastasizing pleomorphic adenoma of the parotid gland involving locoregional lymph nodes

Carcinoma ex-pleomorphic adenoma (PA) is a complex group of malignant neoplasms arising in PA. When microscopic features of the neoplastic cells are representative of carcinoma, the pathologist can easily make a definite diagnosis, but when worrisome morphology is replaced by metastatic behavior, the metastasizing PA (MPA) is a diagnostic challenge for the pathologist. Here, we present an unusual MPA to cervical lymph nodes and discuss diagnostic challenges.