Occult parotid involvement in early-stage squamous cell carcinoma of the external auditory canal.

Background The importance of elective parotidectomy in early-stage squamous cell carcinoma (SCC) of the external auditory canal (EAC) is not well established. Methods A retrospective study of 43 patients with early-stage SCC of the EAC who underwent parotidectomy in conjunction with lateral temporal bone resection at three centers. Results Overall occult parotid involvement (OPI) rate in early-stage SCC of the EAC was 13.9% (6/43). When considering both the anteroposterior position and the bony-cartilaginous position, patients with SCC in both the anterior wall and cartilaginous portion exhibited significantly higher OPI than other locations (37.5% vs. 0%, p = 0.001), with an increase in the OPI predictive value. Conclusion SCC located in either the anterior wall of the EAC or the cartilaginous portion of the EAC or both simultaneously showed a high prevalence of OPI, and elective parotidectomy should be considered in those patients.