Rare Malignancies of the Nasopharynx-25-Year Clinical Experience of a Medical Center

Abstract

Purpose: Nasopharyngeal malignancies, other than squamous cell carcinoma and undifferentiated carcinoma, are rare. We investigated the clinical manifestations and treatment outcomes of patients with rare nasopharyngeal malignancies over a 25-year period. Materials and Methods: From January 1983 to December 2008, a total of 2113 patients with nasopharyngeal malignancies were registered in our radiotherapy database. Only seven eligible patients with rare malignancies of the nasopharynx were found. We retrospectively reviewed hospital charts, radiotherapy records, and imaging studies. The clinical courses and final outcomes were analyzed. Survival was compared with another group of patients with stage II-IVb conventional nasopharyngeal carcinoma (NPC). treated by concomitant chemoradiotherapy. Results: The incidence of rare nasopharyngeal malignancies was only 0.33%. The pathologic diagnoses were three rare carcinomas (adenocarcinoma, mucoepidermoid carcinoma, and small cell carcinoma), three lymphomas and one rhabdomyosarcoma. The initial manifestations were similar to conventional NPC. Two patients were misdiagnosed with conventional NPC (undifferentiated carcinoma), but this was revised to rhabdomyosarcoma and malignant lymphoma when distant sites relapsed. The overall survival and progression-free survival of the study group were significantly worse than conventional NPC (42.9% vs. 74.8%, P=0.027; 42.9% vs. 71.7%, P=0.016, respectively). Conclusion: Rare malignancies arising from the nasopharynx consist of several different pathologies. The accurate diagnosis of rare malignancies of the nasopharynx depends on high index of suspicious of pathologist. The treatment outcome is worse than conventional NPC.