Primary Mucoepidermoid Carcinoma Arising from Ectopic Salivary Tissue within an Intraparotid Lymph Node.

Ectopic salivary tissue is commonly found in intraparotid and periparotid lymph nodes. Warthin tumor is the most common tumor arising in ectopic salivary gland tissue and in intraparotid lymph nodes. Although rare, neoplastic transformation of the ectopic salivary tissues is conceivable and other types of salivary gland neoplasms arising in intraparotid lymph nodes have been reported. Herein we report a rare case of a 32-year-old Kuwaiti male who presented with a mass in the right parotid gland. A preoperative fine needle aspiration suggested Warthin tumor. The patient underwent a superficial parotidectomy. The specimen showed a mass within the parotid parenchyma abutting the deep margin. Hematoxylin and Eosin stained sections of the lesion showed solid islands and cysts composed of epidermoid cells, mucus cells, and intermixed smaller "intermediate" cells within an intraparotid lymph node. The tumor was seen infiltrating the parotid parenchyma at the deep margin. Metastasis from distant sites was ruled out clinically, and the diagnosis rendered was MEC, low-grade, arising from ectopic salivary tissue in an intraparotid lymph node. Such cases are extremely rare and the presence of malignancies within lymph nodes may pose a diagnostic pitfall, which can affect patient management.