A parotid gland mass as an initial metastatic manifestation of nasopharyngeal carcinoma

Abstract

80% of salivary gland tumors are of parotid origin; of these, 80% are benign and 20% are malignant. Metastases are rarely found in the parotid gland. Nasopharyngeal carcinoma (NPC) metastasis to the parotid gland is even rarer. We present a case of a parotid mass as an initial manifestation of NPC metastasis. A 68 year-old male patient suffered from a tender, firm and palpable mass and numbness in right infra-auricular region for one month. Contrast-enhanced computed tomography (CT) showed diffuse contrast enhancement of the right parotid gland, bilateral neck level II enlarged lymph nodes, and a subtle bulging lesion at the nasopharynx. Ultrasonography (US) demonstrated hypoechoic lymph nodes in right parotid gland and right neck level II area. Endoscopy disclosed a bulging lesion in the nasopharynx. US-guided fine-needle aspiration biopsy (FNAB) for the lymph node in right intraparotid region showed positive malignant cells. Excision of the right parotid gland mass revealed lymphoepithelial carcinoma. Biopsy of the nasopharyngeal mass demonstrated undifferentiated nasopharyngeal carcinoma. Therefore, NPC metastasis to the parotid gland was confirmed. A preoperative FNAB of the parotid mass plays a key role in the treatment decision-making process. When associated with a subtle bulging nasopharyngeal lesion on CT, the possibility of NPC with parotid gland metastasis, although rare, should be kept in mind because such findings may have a major impact on the patient management Keywords: Nasopharyngeal carcinoma, Parotid gland metastasis